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https://github.com/danbulant/Cosmos
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896 lines
34 KiB
C#
896 lines
34 KiB
C#
/****************************************************************************
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*
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* LibJpeg.Net
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* Copyright (c) 2008-2011, Bit Miracle
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* Neither the name of the Bit Miracle nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS Software IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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* IS" AND Any EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BIT MIRACLE BE
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* LIABLE FOR Any DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON Any THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN Any WAY OUT OF THE USE OF THIS Software, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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****************************************************************************
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*
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* Copyright (C) 1994-1996, Thomas G. Lane.
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* This file is part of the Independent JPEG Group's software.
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*
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****************************************************************************
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*
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* This file contains routines to read input images in Microsoft "BMP"
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* format (MS Windows 3.x, OS/2 1.x, and OS/2 2.x flavors).
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* Currently, only 8-bit and 24-bit images are supported, not 1-bit or
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* 4-bit (feeding such low-depth images into JPEG would be silly anyway).
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* Also, we don't support RLE-compressed files.
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*
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* Original code was contributed by James Arthur Boucher.
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* This file contains routines to write output images in Microsoft "BMP"
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* format (MS Windows 3.x and OS/2 1.x flavors).
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* Either 8-bit colormapped or 24-bit full-color format can be written.
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* No compression is supported.
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*
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* These routines may need modification for non-Unix environments or
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* specialized applications. As they stand, they assume output to
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* an ordinary stdio stream.
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*
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* This code contributed by James Arthur Boucher.
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*
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* To support 12-bit JPEG data, we'd have to scale output down to 8 bits.
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* This is not yet implemented.
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*
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* Since BMP stores scanlines bottom-to-top, we have to invert the image
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* from JPEG's top-to-bottom order. To do this, we save the outgoing data
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* in a virtual array during put_pixel_row calls, then actually emit the
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* BMP file during finish_output. The virtual array contains one byte per
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* pixel if the output is grayscale or colormapped, three if it is full color.
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*/
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using System;
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using System.Collections.Generic;
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using System.Text;
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using System.IO;
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using BitMiracle.LibJpeg;
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namespace GuessKernel.ImageFormats
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{
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#region BmpCompressor
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class BmpCompressor : JpegCompressor
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{
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/* Target file spec; filled in by djpeg.c after object is created. */
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public Stream output_file;
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/* Output pixel-row buffer. Created by module init or start_output.
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* Width is cinfo.output_width * cinfo.output_components;
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* height is buffer_height.
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*/
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public byte[][] buffer;
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public int buffer_height;
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private JpegDecompressor cinfo;
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private bool m_putGrayRows;
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private bool is_os2; /* saves the OS2 format request flag */
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private JpegVirtualArray<byte> whole_image; /* needed to reverse row order */
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private int data_width; /* bytes per row */
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private int row_width; /* physical width of one row in the BMP file */
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private int pad_bytes; /* number of padding bytes needed per row */
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private int cur_output_row; /* next row# to write to virtual array */
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public BmpCompressor(JpegDecompressor cinfo, bool is_os2)
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{
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this.cinfo = cinfo;
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this.is_os2 = is_os2;
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if (cinfo.Out_color_space == ColorSpace.Grayscale)
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{
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m_putGrayRows = true;
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}
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else if (cinfo.Out_color_space == ColorSpace.RGB)
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{
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if (cinfo.Quantize_colors)
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m_putGrayRows = true;
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else
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m_putGrayRows = false;
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}
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else
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{
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throw new Exception("BMP output must be grayscale or RGB");
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}
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/* Calculate output image dimensions so we can allocate space */
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cinfo.jpeg_calc_output_dimensions();
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/* Determine width of rows in the BMP file (padded to 4-byte boundary). */
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row_width = cinfo.Output_width * cinfo.Output_components;
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data_width = row_width;
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while ((row_width & 3) != 0)
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row_width++;
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pad_bytes = row_width - data_width;
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/* Allocate space for inversion array, prepare for write pass */
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whole_image = JpegCommonBase.CreateSamplesArray(row_width, cinfo.Output_height);
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whole_image.ErrorProcessor = cinfo;
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cur_output_row = 0;
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/* Create decompressor output buffer. */
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buffer = JpegCommonBase.AllocJpegSamples(row_width, 1);
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buffer_height = 1;
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}
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public BmpCompressor(JpegDecompressor cinfo, Stream output, bool is_os2) : this(cinfo, is_os2)
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{
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this.output_file = output;
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}
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/// <summary>
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/// Startup: normally writes the file header.
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/// In this module we may as well postpone everything until finish_output.
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/// </summary>
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public void start_output()
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{
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/* no work here */
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}
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/// <summary>
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/// Write some pixel data.
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/// In this module rows_supplied will always be 1.
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/// </summary>
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public void put_pixel_rows(int rows_supplied)
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{
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if (m_putGrayRows)
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put_gray_rows(rows_supplied);
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else
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put_24bit_rows(rows_supplied);
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}
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/// <summary>
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/// Finish up at the end of the file.
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/// Here is where we really output the BMP file.
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/// </summary>
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public void finish_output()
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{
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/* Write the header and colormap */
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if (is_os2)
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write_os2_header();
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else
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write_bmp_header();
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/* Write the file body from our virtual array */
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for (int row = cinfo.Output_height; row > 0; row--)
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{
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byte[][] image_ptr = whole_image.Access(row - 1, 1);
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int imageIndex = 0;
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for (int col = row_width; col > 0; col--)
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{
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output_file.WriteByte(image_ptr[0][imageIndex]);
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imageIndex++;
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}
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}
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/* Make sure we wrote the output file OK */
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output_file.Flush();
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}
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/// <summary>
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/// Write some pixel data.
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/// In this module rows_supplied will always be 1.
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///
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/// This version is for writing 24-bit pixels
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/// </summary>
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private void put_24bit_rows(int rows_supplied)
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{
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/* Access next row in virtual array */
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byte[][] image_ptr = whole_image.Access(cur_output_row, 1);
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cur_output_row++;
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/* Transfer data. Note destination values must be in BGR order
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* (even though Microsoft's own documents say the opposite).
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*/
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int bufferIndex = 0;
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int imageIndex = 0;
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for (int col = cinfo.Output_width; col > 0; col--)
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{
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image_ptr[0][imageIndex + 2] = buffer[0][bufferIndex]; /* can omit GETJSAMPLE() safely */
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bufferIndex++;
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image_ptr[0][imageIndex + 1] = buffer[0][bufferIndex];
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bufferIndex++;
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image_ptr[0][imageIndex] = buffer[0][bufferIndex];
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bufferIndex++;
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imageIndex += 3;
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}
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/* Zero out the pad bytes. */
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int pad = pad_bytes;
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while (--pad >= 0)
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{
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image_ptr[0][imageIndex] = 0;
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imageIndex++;
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}
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}
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/// <summary>
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/// Write some pixel data.
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/// In this module rows_supplied will always be 1.
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///
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/// This version is for grayscale OR quantized color output
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/// </summary>
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private void put_gray_rows(int rows_supplied)
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{
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/* Access next row in virtual array */
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byte[][] image_ptr = whole_image.Access(cur_output_row, 1);
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cur_output_row++;
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/* Transfer data. */
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int index = 0;
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for (int col = cinfo.Output_width; col > 0; col--)
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{
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image_ptr[0][index] = buffer[0][index];/* can omit GETJSAMPLE() safely */
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index++;
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}
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/* Zero out the pad bytes. */
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int pad = pad_bytes;
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while (--pad >= 0)
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{
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image_ptr[0][index] = 0;
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index++;
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}
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}
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/// <summary>
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/// Write a Windows-style BMP file header, including colormap if needed
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/// </summary>
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private void write_bmp_header()
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{
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int bits_per_pixel;
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int cmap_entries;
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/* Compute colormap size and total file size */
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if (cinfo.Out_color_space == ColorSpace.RGB)
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{
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if (cinfo.Quantize_colors)
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{
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/* Colormapped RGB */
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bits_per_pixel = 8;
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cmap_entries = 256;
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}
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else
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{
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/* Unquantized, full color RGB */
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bits_per_pixel = 24;
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cmap_entries = 0;
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}
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}
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else
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{
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/* Grayscale output. We need to fake a 256-entry colormap. */
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bits_per_pixel = 8;
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cmap_entries = 256;
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}
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/* File size */
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int headersize = 14 + 40 + cmap_entries * 4; /* Header and colormap */
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int bfSize = headersize + row_width * cinfo.Output_height;
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/* Set unused fields of header to 0 */
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byte[] bmpfileheader = new byte[14];
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byte[] bmpinfoheader = new byte[40];
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/* Fill the file header */
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bmpfileheader[0] = 0x42; /* first 2 bytes are ASCII 'B', 'M' */
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bmpfileheader[1] = 0x4D;
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PUT_4B(bmpfileheader, 2, bfSize); /* bfSize */
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/* we leave bfReserved1 & bfReserved2 = 0 */
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PUT_4B(bmpfileheader, 10, headersize); /* bfOffBits */
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/* Fill the info header (Microsoft calls this a BITMAPINFOHEADER) */
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PUT_2B(bmpinfoheader, 0, 40); /* biSize */
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PUT_4B(bmpinfoheader, 4, cinfo.Output_width); /* biWidth */
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PUT_4B(bmpinfoheader, 8, cinfo.Output_height); /* biHeight */
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PUT_2B(bmpinfoheader, 12, 1); /* biPlanes - must be 1 */
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PUT_2B(bmpinfoheader, 14, bits_per_pixel); /* biBitCount */
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/* we leave biCompression = 0, for none */
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/* we leave biSizeImage = 0; this is correct for uncompressed data */
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if (cinfo.Density_unit == DensityUnit.DotsCm)
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{
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/* if have density in dots/cm, then */
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PUT_4B(bmpinfoheader, 24, (int)(cinfo.X_density * 100)); /* XPels/M */
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PUT_4B(bmpinfoheader, 28, (int)(cinfo.Y_density * 100)); /* XPels/M */
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}
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PUT_2B(bmpinfoheader, 32, cmap_entries); /* biClrUsed */
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/* we leave biClrImportant = 0 */
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try
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{
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output_file.Write(bmpfileheader, 0, 14);
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}
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catch
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{
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throw new Exception("An error occurred when writing the output file. Perhaps your out of disk space?");
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}
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try
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{
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output_file.Write(bmpinfoheader, 0, 40);
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}
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catch
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{
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throw new Exception("An error occurred when writing the output file. Perhaps your out of disk space?");
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}
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if (cmap_entries > 0)
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write_colormap(cmap_entries, 4);
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}
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/// <summary>
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/// Write an OS2-style BMP file header, including colormap if needed
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/// </summary>
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private void write_os2_header()
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{
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int bits_per_pixel;
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int cmap_entries;
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/* Compute colormap size and total file size */
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if (cinfo.Out_color_space == ColorSpace.RGB)
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{
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if (cinfo.Quantize_colors)
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{
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/* Colormapped RGB */
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bits_per_pixel = 8;
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cmap_entries = 256;
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}
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else
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{
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/* Unquantized, full color RGB */
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bits_per_pixel = 24;
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cmap_entries = 0;
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}
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}
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else
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{
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/* Grayscale output. We need to fake a 256-entry colormap. */
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bits_per_pixel = 8;
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cmap_entries = 256;
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}
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/* File size */
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int headersize = 14 + 12 + cmap_entries * 3; /* Header and colormap */
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int bfSize = headersize + row_width * cinfo.Output_height;
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/* Set unused fields of header to 0 */
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byte[] bmpfileheader = new byte[14];
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byte[] bmpcoreheader = new byte[12];
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/* Fill the file header */
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bmpfileheader[0] = 0x42; /* first 2 bytes are ASCII 'B', 'M' */
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bmpfileheader[1] = 0x4D;
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PUT_4B(bmpfileheader, 2, bfSize); /* bfSize */
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/* we leave bfReserved1 & bfReserved2 = 0 */
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PUT_4B(bmpfileheader, 10, headersize); /* bfOffBits */
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/* Fill the info header (Microsoft calls this a BITMAPCOREHEADER) */
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PUT_2B(bmpcoreheader, 0, 12); /* bcSize */
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PUT_2B(bmpcoreheader, 4, cinfo.Output_width); /* bcWidth */
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PUT_2B(bmpcoreheader, 6, cinfo.Output_height); /* bcHeight */
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PUT_2B(bmpcoreheader, 8, 1); /* bcPlanes - must be 1 */
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PUT_2B(bmpcoreheader, 10, bits_per_pixel); /* bcBitCount */
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try
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{
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output_file.Write(bmpfileheader, 0, 14);
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}
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catch
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{
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throw new Exception("An error occurred when writing the output file. Perhaps your out of disk space?");
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}
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try
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{
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output_file.Write(bmpcoreheader, 0, 12);
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}
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catch
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{
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throw new Exception("An error occurred when writing the output file. Perhaps your out of disk space?");
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}
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if (cmap_entries > 0)
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write_colormap(cmap_entries, 3);
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}
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/// <summary>
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/// Write the colormap.
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/// Windows uses BGR0 map entries; OS/2 uses BGR entries.
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/// </summary>
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private void write_colormap(int map_colors, int map_entry_size)
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{
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byte[][] colormap = cinfo.Colormap;
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int num_colors = cinfo.Actual_number_of_colors;
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int i = 0;
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if (colormap != null)
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{
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if (cinfo.Out_color_components == 3)
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{
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/* Normal case with RGB colormap */
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for (i = 0; i < num_colors; i++)
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{
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output_file.WriteByte(colormap[2][i]);
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output_file.WriteByte(colormap[1][i]);
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output_file.WriteByte(colormap[0][i]);
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if (map_entry_size == 4)
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output_file.WriteByte(0);
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}
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}
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else
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{
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/* Grayscale colormap (only happens with grayscale quantization) */
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for (i = 0; i < num_colors; i++)
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{
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output_file.WriteByte(colormap[0][i]);
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output_file.WriteByte(colormap[0][i]);
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output_file.WriteByte(colormap[0][i]);
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if (map_entry_size == 4)
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output_file.WriteByte(0);
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}
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}
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}
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else
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{
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/* If no colormap, must be grayscale data. Generate a linear "map". */
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for (i = 0; i < 256; i++)
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{
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output_file.WriteByte((byte)i);
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output_file.WriteByte((byte)i);
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output_file.WriteByte((byte)i);
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if (map_entry_size == 4)
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output_file.WriteByte(0);
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}
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}
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/* Pad colormap with zeros to ensure specified number of colormap entries */
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if (i > map_colors)
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throw new Exception(string.Format("Output file format cannot handle %d colormap entries", i));
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for (; i < map_colors; i++)
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{
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output_file.WriteByte(0);
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output_file.WriteByte(0);
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output_file.WriteByte(0);
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if (map_entry_size == 4)
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output_file.WriteByte(0);
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}
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}
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private static void PUT_2B(byte[] array, int offset, int value)
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{
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array[offset] = (byte)((value) & 0xFF);
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array[offset + 1] = (byte)(((value) >> 8) & 0xFF);
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}
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private static void PUT_4B(byte[] array, int offset, int value)
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{
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array[offset] = (byte)((value) & 0xFF);
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array[offset + 1] = (byte)(((value) >> 8) & 0xFF);
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array[offset + 2] = (byte)(((value) >> 16) & 0xFF);
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array[offset + 3] = (byte)(((value) >> 24) & 0xFF);
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}
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}
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#endregion
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#region JpegDecompressor
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class BmpDecompressor : JpegDecompressor
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{
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private enum PixelRowsMethod
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{
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preload,
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use8bit,
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use24bit
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}
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public Stream input_file;
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public byte[][] buffer;
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public uint buffer_height;
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private JpegCompressor cinfo;
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private PixelRowsMethod m_pixelRowsMethod;
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// BMP colormap (converted to my format)
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private byte[][] colormap;
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// Needed to reverse row order
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private JpegVirtualArray<byte> whole_image;
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// Current source row number
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private int source_row;
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// Physical width of scanlines in file
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private int row_width;
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// remembers 8- or 24-bit format
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private int bits_per_pixel;
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public BmpDecompressor(JpegCompressor cinfo)
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{
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this.cinfo = cinfo;
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}
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public BmpDecompressor(JpegCompressor cinfo, Stream input)
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{
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this.cinfo = cinfo;
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this.input_file = input;
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}
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/// <summary>
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/// Read the file header; detects image size and component count.
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/// </summary>
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public void start_input()
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{
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byte[] bmpfileheader = new byte[14];
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/* Read and verify the bitmap file header */
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if (!ReadOK(input_file, bmpfileheader, 0, 14))
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throw new Exception("The file ended pre-maturely. Perhaps the file is corrupt?");
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if (GET_2B(bmpfileheader, 0) != 0x4D42) /* 'BM' */
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throw new Exception("Not a BMP file. File header doesn't start with BM");
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int bfOffBits = GET_4B(bmpfileheader, 10);
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/* We ignore the remaining file header fields */
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/* The info header might be 12 bytes (OS/2 1.x), 40 bytes (Windows),
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* or 64 bytes (OS/2 2.x). Check the first 4 bytes to find out which.
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*/
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byte[] bmpinfoheader = new byte[64];
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if (!ReadOK(input_file, bmpinfoheader, 0, 4))
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throw new Exception("The file ended pre-maturely. Perhaps the file is corrupt?");
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int headerSize = GET_4B(bmpinfoheader, 0);
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if (headerSize < 12 || headerSize > 64)
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throw new Exception("Invalid BMP file: Bad Header Length.");
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if (!ReadOK(input_file, bmpinfoheader, 4, headerSize - 4))
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throw new Exception("The file ended pre-maturely. Perhaps the file is corrupt?");
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int biWidth = 0; /* initialize to avoid compiler warning */
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int biHeight = 0;
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int biPlanes;
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int biCompression;
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int biXPelsPerMeter;
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int biYPelsPerMeter;
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int biClrUsed = 0;
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int mapentrysize = 0; /* 0 indicates no colormap */
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switch (headerSize)
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{
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case 12:
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/* Decode OS/2 1.x header (Microsoft calls this a BITMAPCOREHEADER) */
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biWidth = GET_2B(bmpinfoheader, 4);
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biHeight = GET_2B(bmpinfoheader, 6);
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biPlanes = GET_2B(bmpinfoheader, 8);
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bits_per_pixel = GET_2B(bmpinfoheader, 10);
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switch (bits_per_pixel)
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{
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case 8:
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/* colormapped image */
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mapentrysize = 3; /* OS/2 uses RGBTRIPLE colormap */
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break;
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case 24:
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/* RGB image */
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break;
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default:
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throw new Exception("Bad Color Depth: Only 8-bit and 24-bit BMP files are supported.");
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}
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if (biPlanes != 1)
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throw new Exception("Invalid BMP file: biPlanes is not equal to 1");
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break;
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case 40:
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case 64:
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/* Decode Windows 3.x header (Microsoft calls this a BITMAPINFOHEADER) */
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/* or OS/2 2.x header, which has additional fields that we ignore */
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biWidth = GET_4B(bmpinfoheader, 4);
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biHeight = GET_4B(bmpinfoheader, 8);
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biPlanes = GET_2B(bmpinfoheader, 12);
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bits_per_pixel = GET_2B(bmpinfoheader, 14);
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biCompression = GET_4B(bmpinfoheader, 16);
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biXPelsPerMeter = GET_4B(bmpinfoheader, 24);
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biYPelsPerMeter = GET_4B(bmpinfoheader, 28);
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biClrUsed = GET_4B(bmpinfoheader, 32);
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/* biSizeImage, biClrImportant fields are ignored */
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switch (bits_per_pixel)
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{
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case 8:
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/* colormapped image */
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mapentrysize = 4; /* Windows uses RGBQUAD colormap */
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break;
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case 24:
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/* RGB image */
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break;
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default:
|
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throw new Exception("Bad Color Depth: Only 8-bit and 24-bit BMP files are supported.");
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}
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if (biPlanes != 1)
|
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throw new Exception("Invalid BMP file: biPlanes is not equal to 1");
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if (biCompression != 0)
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throw new Exception("Sorry, compressed BMPs not yet supported.");
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if (biXPelsPerMeter > 0 && biYPelsPerMeter > 0)
|
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{
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/* Set JFIF density parameters from the BMP data */
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cinfo.X_density = (short)(biXPelsPerMeter / 100); /* 100 cm per meter */
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cinfo.Y_density = (short)(biYPelsPerMeter / 100);
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cinfo.Density_unit = DensityUnit.DotsCm;
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}
|
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break;
|
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default:
|
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throw new Exception("Invalid BMP file: Bad Header Length.");
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}
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|
|
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/* Compute distance to bitmap data --- will adjust for colormap below */
|
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int bPad = bfOffBits - (headerSize + 14);
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/* Read the colormap, if any */
|
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if (mapentrysize > 0)
|
|
{
|
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if (biClrUsed <= 0)
|
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biClrUsed = 256; /* assume it's 256 */
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else if (biClrUsed > 256)
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throw new Exception("Unsupported BMP colormap format.");
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/* Allocate space to store the colormap */
|
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colormap = JpegCommonBase.AllocJpegSamples(biClrUsed, 3);
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/* and read it from the file */
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read_colormap(biClrUsed, mapentrysize);
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/* account for size of colormap */
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bPad -= biClrUsed * mapentrysize;
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}
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/* Skip any remaining pad bytes */
|
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if (bPad < 0) /* incorrect bfOffBits value? */
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throw new Exception("Invalid BMP file: Bad Header Length.");
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while (--bPad >= 0)
|
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read_byte();
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|
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/* Compute row width in file, including padding to 4-byte boundary */
|
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if (bits_per_pixel == 24)
|
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row_width = biWidth * 3;
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else
|
|
row_width = biWidth;
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while ((row_width & 3) != 0)
|
|
row_width++;
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/* Allocate space for inversion array, prepare for preload pass */
|
|
whole_image = JpegCommonBase.CreateSamplesArray(row_width, biHeight);
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|
whole_image.ErrorProcessor = cinfo;
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m_pixelRowsMethod = PixelRowsMethod.preload;
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/* Allocate one-row buffer for returned data */
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buffer = JpegCommonBase.AllocJpegSamples(biWidth * 3, 1);
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buffer_height = 1;
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cinfo.In_color_space = ColorSpace.RGB;
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cinfo.Input_components = 3;
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cinfo.Data_precision = 8;
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cinfo.Image_width = biWidth;
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cinfo.Image_height = biHeight;
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}
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public int get_pixel_rows()
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{
|
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if (m_pixelRowsMethod == PixelRowsMethod.preload)
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return preload_image();
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else if (m_pixelRowsMethod == PixelRowsMethod.use8bit)
|
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return get_8bit_row();
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return get_24bit_row();
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}
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|
|
|
// Finish up at the end of the file.
|
|
public void finish_input()
|
|
{
|
|
// no work
|
|
}
|
|
|
|
|
|
#region 8-Bit Support
|
|
/// <summary>
|
|
/// Read one row of pixels.
|
|
/// The image has been read into the whole_image array, but is otherwise
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|
/// unprocessed. We must read it out in top-to-bottom row order, and if
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|
/// it is an 8-bit image, we must expand colormapped pixels to 24bit format.
|
|
/// This version is for reading 8-bit colormap indexes.
|
|
/// </summary>
|
|
private int get_8bit_row()
|
|
{
|
|
/* Fetch next row from virtual array */
|
|
source_row--;
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|
|
|
byte[][] image_ptr = whole_image.Access(source_row, 1);
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|
|
|
/* Expand the colormap indexes to real data */
|
|
int imageIndex = 0;
|
|
int outIndex = 0;
|
|
for (int col = cinfo.Image_width; col > 0; col--)
|
|
{
|
|
int t = image_ptr[0][imageIndex];
|
|
imageIndex++;
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|
|
|
buffer[0][outIndex] = colormap[0][t]; /* can omit GETbyte() safely */
|
|
outIndex++;
|
|
buffer[0][outIndex] = colormap[1][t];
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|
outIndex++;
|
|
buffer[0][outIndex] = colormap[2][t];
|
|
outIndex++;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
#endregion
|
|
|
|
#region 24-Bit Support
|
|
/// <summary>
|
|
/// Read one row of pixels.
|
|
/// The image has been read into the whole_image array, but is otherwise
|
|
/// unprocessed. We must read it out in top-to-bottom row order, and if
|
|
/// it is an 8-bit image, we must expand colormapped pixels to 24bit format.
|
|
/// This version is for reading 24-bit pixels.
|
|
/// </summary>
|
|
private int get_24bit_row()
|
|
{
|
|
/* Fetch next row from virtual array */
|
|
source_row--;
|
|
byte[][] image_ptr = whole_image.Access(source_row, 1);
|
|
|
|
/* Transfer data. Note source values are in BGR order
|
|
* (even though Microsoft's own documents say the opposite).
|
|
*/
|
|
int imageIndex = 0;
|
|
int outIndex = 0;
|
|
|
|
for (int col = cinfo.Image_width; col > 0; col--)
|
|
{
|
|
buffer[0][outIndex + 2] = image_ptr[0][imageIndex]; /* can omit GETbyte() safely */
|
|
imageIndex++;
|
|
buffer[0][outIndex + 1] = image_ptr[0][imageIndex];
|
|
imageIndex++;
|
|
buffer[0][outIndex] = image_ptr[0][imageIndex];
|
|
imageIndex++;
|
|
outIndex += 3;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
#endregion
|
|
|
|
|
|
/// <summary>
|
|
/// This method loads the image into whole_image during the first call on
|
|
/// get_pixel_rows.
|
|
/// </summary>
|
|
private int preload_image()
|
|
{
|
|
/* Read the data into a virtual array in input-file row order. */
|
|
for (int row = 0; row < cinfo.Image_height; row++)
|
|
{
|
|
|
|
byte[][] image_ptr = whole_image.Access(row, 1);
|
|
int imageIndex = 0;
|
|
for (int col = row_width; col > 0; col--)
|
|
{
|
|
/* inline copy of read_byte() for speed */
|
|
int c = input_file.ReadByte();
|
|
if (c == -1)
|
|
throw new Exception("The file ended pre-maturely. Perhaps the file is corrupt?");
|
|
|
|
image_ptr[0][imageIndex] = (byte)c;
|
|
imageIndex++;
|
|
}
|
|
}
|
|
|
|
/* Set up to read from the virtual array in top-to-bottom order */
|
|
switch (bits_per_pixel)
|
|
{
|
|
case 8:
|
|
m_pixelRowsMethod = PixelRowsMethod.use8bit;
|
|
break;
|
|
case 24:
|
|
m_pixelRowsMethod = PixelRowsMethod.use24bit;
|
|
break;
|
|
default:
|
|
throw new Exception("Bad Color Depth: Only 8-bit and 24-bit BMP files are supported.");
|
|
}
|
|
|
|
source_row = cinfo.Image_height;
|
|
|
|
/* And read the first row */
|
|
return get_pixel_rows();
|
|
}
|
|
|
|
// Read next byte from BMP file
|
|
private int read_byte()
|
|
{
|
|
int c = input_file.ReadByte();
|
|
if (c == -1)
|
|
throw new Exception("The file ended pre-maturely. Perhaps the file is corrupt?");
|
|
|
|
return c;
|
|
}
|
|
|
|
// Read the colormap from a BMP file
|
|
private void read_colormap(int cmaplen, int mapentrysize)
|
|
{
|
|
switch (mapentrysize)
|
|
{
|
|
case 3:
|
|
/* BGR format (occurs in OS/2 files) */
|
|
for (int i = 0; i < cmaplen; i++)
|
|
{
|
|
colormap[2][i] = (byte)read_byte();
|
|
colormap[1][i] = (byte)read_byte();
|
|
colormap[0][i] = (byte)read_byte();
|
|
}
|
|
break;
|
|
case 4:
|
|
/* BGR0 format (occurs in MS Windows files) */
|
|
for (int i = 0; i < cmaplen; i++)
|
|
{
|
|
colormap[2][i] = (byte)read_byte();
|
|
colormap[1][i] = (byte)read_byte();
|
|
colormap[0][i] = (byte)read_byte();
|
|
read_byte();
|
|
}
|
|
break;
|
|
default:
|
|
throw new Exception("Unsupported BMP colormap format.");
|
|
}
|
|
}
|
|
|
|
private static bool ReadOK(Stream file, byte[] buffer, int offset, int len)
|
|
{
|
|
int read = file.Read(buffer, offset, len);
|
|
return (read == len);
|
|
}
|
|
|
|
private static int GET_2B(byte[] array, int offset)
|
|
{
|
|
return (int)array[offset] + ((int)array[offset + 1] << 8);
|
|
}
|
|
|
|
private static int GET_4B(byte[] array, int offset)
|
|
{
|
|
return (int)array[offset] + ((int)array[offset + 1] << 8) + ((int)array[offset + 2] << 16) + ((int)array[offset + 3] << 24);
|
|
}
|
|
}
|
|
#endregion
|
|
|
|
}
|