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gimp/plug-ins/xjt/xjpeg.c

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/* The GIMP -- an image manipulation program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* JPEG loading and saving routines adapted for the GIMP XJT fileformat
* -Wolfgang Hofer
*
* This filter is heavily based upon the "example.c" file in libjpeg.
* In fact most of the loading and saving code was simply cut-and-pasted
* from that file. The filter, therefore, also uses libjpeg.
*/
/* revision history:
* version 1.1.15a; 2000/01/25 hof: use g_malloc, g_free
* version 1.00.00; 1998/10/26 hof: 1.st (pre) release
*/
#include "config.h"
#include <setjmp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Include for External Libraries */
#include <jpeglib.h>
/* GIMP includes */
#include "libgimp/gimp.h"
#include "xjpeg.h"
extern int xjt_debug;
/* Declare local functions.
*/
typedef struct my_error_mgr {
struct jpeg_error_mgr pub; /* "public" fields */
jmp_buf setjmp_buffer; /* for return to caller */
} *my_error_ptr;
/*
* Here's the routine that will replace the standard error_exit method:
*/
static void
my_error_exit (j_common_ptr cinfo)
{
/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
my_error_ptr myerr = (my_error_ptr) cinfo->err;
/* Always display the message. */
/* We could postpone this until after returning, if we chose. */
(*cinfo->err->output_message) (cinfo);
/* Return control to the setjmp point */
longjmp (myerr->setjmp_buffer, 1);
}
/* ============================================================================
* xjpg_load_layer
* load layer from jpeg file
* ============================================================================
*/
gint32
xjpg_load_layer (char *filename,
gint32 image_id,
int image_type,
char *layer_name,
gdouble layer_opacity,
GimpLayerModeEffects layer_mode
)
{
GimpPixelRgn l_pixel_rgn;
GimpDrawable *l_drawable;
gint32 l_layer_id;
GimpImageType l_layer_type;
struct jpeg_decompress_struct cinfo;
struct my_error_mgr jerr;
FILE *infile;
guchar *l_buf;
guchar **l_rowbuf;
int l_tile_height;
int l_scanlines;
int l_idx, l_start, l_end;
/* We set up the normal JPEG error routines. */
cinfo.err = jpeg_std_error (&jerr.pub);
jerr.pub.error_exit = my_error_exit;
l_layer_type = GIMP_GRAY_IMAGE;
if ((infile = fopen (filename, "rb")) == NULL)
{
g_warning ("can't open \"%s\"\n", filename);
return -1;
}
/* Establish the setjmp return context for my_error_exit to use. */
if (setjmp (jerr.setjmp_buffer))
{
/* If we get here, the JPEG code has signaled an error.
* We need to clean up the JPEG object, close the input file, and return.
*/
jpeg_destroy_decompress (&cinfo);
if (infile)
fclose (infile);
fprintf(stderr, "XJT: JPEG load error\n");
return -1;
}
/* Now we can initialize the JPEG decompression object. */
jpeg_create_decompress (&cinfo);
/* Step 2: specify data source (eg, a file) */
jpeg_stdio_src (&cinfo, infile);
/* Step 3: read file parameters with jpeg_read_header() */
(void) jpeg_read_header (&cinfo, TRUE);
/* We can ignore the return value from jpeg_read_header since
* (a) suspension is not possible with the stdio data source, and
* (b) we passed TRUE to reject a tables-only JPEG file as an error.
* See libjpeg.doc for more info.
*/
/* Step 4: set parameters for decompression */
/* In this example, we don't need to change any of the defaults set by
* jpeg_read_header(), so we do nothing here.
*/
/* Step 5: Start decompressor */
jpeg_start_decompress (&cinfo);
/* We may need to do some setup of our own at this point before reading
* the data. After jpeg_start_decompress() we have the correct scaled
* output image dimensions available, as well as the output colormap
* if we asked for color quantization.
* In this example, we need to make an output work buffer of the right size.
*/
/* temporary buffer */
l_tile_height = gimp_tile_height ();
l_buf = g_new (guchar, l_tile_height * cinfo.output_width * cinfo.output_components);
l_rowbuf = g_new (guchar*, l_tile_height);
for (l_idx = 0; l_idx < l_tile_height; l_idx++)
{
l_rowbuf[l_idx] = l_buf + cinfo.output_width * cinfo.output_components * l_idx;
}
/* Check jpeg file for layer type */
switch (cinfo.output_components)
{
case 1:
l_layer_type = GIMP_GRAY_IMAGE;
break;
case 3:
l_layer_type = GIMP_RGB_IMAGE;
break;
default:
fprintf(stderr, "XJT: cant load layer %s (type is not GRAY and not RGB)\n", filename);
fclose (infile);
return -1;
}
l_layer_id = gimp_layer_new (image_id, layer_name,
cinfo.output_width,
cinfo.output_height,
l_layer_type,
layer_opacity,
layer_mode);
if(l_layer_id < 0)
{
fprintf(stderr, "XJT: cant create new layer\n");
fclose (infile);
return -1;
}
l_drawable = gimp_drawable_get (l_layer_id);
gimp_pixel_rgn_init (&l_pixel_rgn, l_drawable, 0, 0, l_drawable->width, l_drawable->height, TRUE, FALSE);
/* Step 6: while (scan lines remain to be read) */
/* jpeg_read_scanlines(...); */
/* Here we use the library's state variable cinfo.output_scanline as the
* loop counter, so that we don't have to keep track ourselves.
*/
while (cinfo.output_scanline < cinfo.output_height)
{
l_start = cinfo.output_scanline;
l_end = cinfo.output_scanline + l_tile_height;
l_end = MIN (l_end, cinfo.output_height);
l_scanlines = l_end - l_start;
for (l_idx = 0; l_idx < l_scanlines; l_idx++)
{
jpeg_read_scanlines (&cinfo, (JSAMPARRAY) &l_rowbuf[l_idx], 1);
}
gimp_pixel_rgn_set_rect (&l_pixel_rgn, l_buf, 0, l_start, l_drawable->width, l_scanlines);
gimp_progress_update ((double) cinfo.output_scanline / (double) cinfo.output_height);
}
/* Step 7: Finish decompression */
jpeg_finish_decompress (&cinfo);
/* We can ignore the return value since suspension is not possible
* with the stdio data source.
*/
/* Step 8: Release JPEG decompression object */
/* This is an important step since it will release a good deal of memory. */
jpeg_destroy_decompress (&cinfo);
/* free up the temporary buffers */
g_free (l_rowbuf);
g_free (l_buf);
/* After finish_decompress, we can close the input file.
* Here we postpone it until after no more JPEG errors are possible,
* so as to simplify the setjmp error logic above. (Actually, I don't
* think that jpeg_destroy can do an error exit, but why assume anything...)
*/
fclose (infile);
/* At this point you may want to check to see whether any corrupt-data
* warnings occurred (test whether jerr.num_warnings is nonzero).
*/
return (l_layer_id);
} /* end xjpg_load_layer */
/* ============================================================================
* xjpg_load_layer_alpha
* load the layers alpha channel from jpeg file.
* ============================================================================
*/
gint
xjpg_load_layer_alpha (char *filename,
gint32 image_id,
gint32 layer_id
)
{
GimpPixelRgn l_pixel_rgn;
GimpDrawable *l_drawable;
GimpImageType l_layer_type;
struct jpeg_decompress_struct cinfo;
struct my_error_mgr jerr;
FILE *infile;
guchar *l_buf;
guchar *l_dstbuf;
guchar **l_rowbuf;
int l_tile_height;
int l_scanlines;
int l_idx, l_start, l_end;
int l_alpha_offset;
guchar *l_buf_ptr;
guchar *l_dstbuf_ptr;
/* We set up the normal JPEG error routines. */
cinfo.err = jpeg_std_error (&jerr.pub);
jerr.pub.error_exit = my_error_exit;
l_layer_type = GIMP_GRAY_IMAGE;
/* add alpha channel */
gimp_layer_add_alpha (layer_id);
if ((infile = fopen (filename, "rb")) == NULL)
{
/* No alpha found, thats OK, use full opaque alpha channel
* (there is no need not store alpha channels on full opaque channels)
* (fixme: if filename exists but is not readable
* we should return -1 to indicate an error
*/
return 0; /* OK */
}
/* Establish the setjmp return context for my_error_exit to use. */
if (setjmp (jerr.setjmp_buffer))
{
/* If we get here, the JPEG code has signaled an error.
* We need to clean up the JPEG object, close the input file, and return.
*/
jpeg_destroy_decompress (&cinfo);
if (infile)
fclose (infile);
fprintf(stderr, "XJT: JPEG alpha load error\n");
return -1;
}
/* Now we can initialize the JPEG decompression object. */
jpeg_create_decompress (&cinfo);
/* Step 2: specify data source (eg, a file) */
jpeg_stdio_src (&cinfo, infile);
/* Step 3: read file parameters with jpeg_read_header() */
(void) jpeg_read_header (&cinfo, TRUE);
/* We can ignore the return value from jpeg_read_header since
* (a) suspension is not possible with the stdio data source, and
* (b) we passed TRUE to reject a tables-only JPEG file as an error.
* See libjpeg.doc for more info.
*/
/* Step 4: set parameters for decompression */
/* In this example, we don't need to change any of the defaults set by
* jpeg_read_header(), so we do nothing here.
*/
/* Step 5: Start decompressor */
jpeg_start_decompress (&cinfo);
/* We may need to do some setup of our own at this point before reading
* the data. After jpeg_start_decompress() we have the correct scaled
* output image dimensions available, as well as the output colormap
* if we asked for color quantization.
* In this example, we need to make an output work buffer of the right size.
*/
/* temporary buffer (for read in jpeg lines) */
l_tile_height = gimp_tile_height ();
l_buf = g_new (guchar, l_tile_height * cinfo.output_width * cinfo.output_components);
l_rowbuf = g_new (guchar*, l_tile_height);
for (l_idx = 0; l_idx < l_tile_height; l_idx++)
{
l_rowbuf[l_idx] = l_buf + cinfo.output_width * cinfo.output_components * l_idx;
}
l_drawable = gimp_drawable_get (layer_id);
if(l_drawable == NULL)
{
fprintf(stderr, "XJT: gimp_drawable_get failed on layer id %d\n", (int)layer_id);
fclose(infile);
return -1;
}
/* Check if jpeg file can be used as alpha channel
*/
if((cinfo.output_components != 1) ||
(cinfo.output_width != l_drawable->width) ||
(cinfo.output_height != l_drawable->height))
{
fprintf(stderr, "XJT: cant load %s as alpha channel\n", filename);
fclose (infile);
return -1;
}
/* buffer to read in the layer and merge with the alpha from jpeg file */
l_dstbuf = g_new (guchar, l_tile_height * l_drawable->width * l_drawable->bpp);
gimp_pixel_rgn_init (&l_pixel_rgn, l_drawable, 0, 0, l_drawable->width, l_drawable->height, TRUE, FALSE);
l_alpha_offset = l_drawable->bpp -1;
/* Step 6: while (scan lines remain to be read) */
/* jpeg_read_scanlines(...); */
/* Here we use the library's state variable cinfo.output_scanline as the
* loop counter, so that we don't have to keep track ourselves.
*/
while (cinfo.output_scanline < cinfo.output_height)
{
l_start = cinfo.output_scanline;
l_end = cinfo.output_scanline + l_tile_height;
l_end = MIN (l_end, cinfo.output_height);
l_scanlines = l_end - l_start;
for (l_idx = 0; l_idx < l_scanlines; l_idx++)
{
jpeg_read_scanlines (&cinfo, (JSAMPARRAY) &l_rowbuf[l_idx], 1);
}
gimp_pixel_rgn_get_rect (&l_pixel_rgn, l_dstbuf, 0, l_start, l_drawable->width, l_scanlines);
/* copy the loaded jpeg data (from buf) to the layers alpha channel data */
l_idx = l_tile_height * l_drawable->width;
l_buf_ptr = l_buf;
l_dstbuf_ptr = l_dstbuf;
while(l_idx--)
{
l_dstbuf_ptr += l_alpha_offset;
*l_dstbuf_ptr++ = *l_buf_ptr++;
}
gimp_pixel_rgn_set_rect (&l_pixel_rgn, l_dstbuf, 0, l_start, l_drawable->width, l_scanlines);
gimp_progress_update ((double) cinfo.output_scanline / (double) cinfo.output_height);
}
/* Step 7: Finish decompression */
jpeg_finish_decompress (&cinfo);
/* We can ignore the return value since suspension is not possible
* with the stdio data source.
*/
/* Step 8: Release JPEG decompression object */
/* This is an important step since it will release a good deal of memory. */
jpeg_destroy_decompress (&cinfo);
/* free up the temporary buffers */
g_free (l_rowbuf);
g_free (l_buf);
g_free (l_dstbuf);
/* After finish_decompress, we can close the input file.
* Here we postpone it until after no more JPEG errors are possible,
* so as to simplify the setjmp error logic above. (Actually, I don't
* think that jpeg_destroy can do an error exit, but why assume anything...)
*/
fclose (infile);
/* At this point you may want to check to see whether any corrupt-data
* warnings occurred (test whether jerr.num_warnings is nonzero).
*/
return (0); /* OK */
} /* xjpg_load_layer_alpha */
/* ============================================================================
* xjpg_load_channel
* load channel from jpeg file
* (call this procedure with drawable_id == -1 to create a new channel,
* if a positive drawable_id is supplied, its content will be overwritten)
* ============================================================================
*/
gint32
xjpg_load_channel (char *filename,
gint32 image_id,
gint32 drawable_id,
char *channel_name,
gdouble channel_opacity,
guchar red, guchar green, guchar blue
)
{
GimpPixelRgn l_pixel_rgn;
GimpDrawable *l_drawable;
gint32 l_drawable_id;
struct jpeg_decompress_struct cinfo;
struct my_error_mgr jerr;
FILE *infile;
guchar *l_buf;
guchar **l_rowbuf;
int l_tile_height;
int l_scanlines;
int l_idx, l_start, l_end;
GimpRGB l_color;
gimp_rgba_set_uchar (&l_color, red, green, blue, 255);
/* We set up the normal JPEG error routines. */
cinfo.err = jpeg_std_error (&jerr.pub);
jerr.pub.error_exit = my_error_exit;
if ((infile = fopen (filename, "rb")) == NULL)
{
g_warning ("can't open \"%s\"\n", filename);
return -1;
}
/* Establish the setjmp return context for my_error_exit to use. */
if (setjmp (jerr.setjmp_buffer))
{
/* If we get here, the JPEG code has signaled an error.
* We need to clean up the JPEG object, close the input file, and return.
*/
jpeg_destroy_decompress (&cinfo);
if (infile)
fclose (infile);
fprintf(stderr, "XJT: JPEG load error\n");
return -1;
}
/* Now we can initialize the JPEG decompression object. */
jpeg_create_decompress (&cinfo);
/* Step 2: specify data source (eg, a file) */
jpeg_stdio_src (&cinfo, infile);
/* Step 3: read file parameters with jpeg_read_header() */
(void) jpeg_read_header (&cinfo, TRUE);
/* We can ignore the return value from jpeg_read_header since
* (a) suspension is not possible with the stdio data source, and
* (b) we passed TRUE to reject a tables-only JPEG file as an error.
* See libjpeg.doc for more info.
*/
/* Step 4: set parameters for decompression */
/* In this example, we don't need to change any of the defaults set by
* jpeg_read_header(), so we do nothing here.
*/
/* Step 5: Start decompressor */
jpeg_start_decompress (&cinfo);
/* We may need to do some setup of our own at this point before reading
* the data. After jpeg_start_decompress() we have the correct scaled
* output image dimensions available, as well as the output colormap
* if we asked for color quantization.
* In this example, we need to make an output work buffer of the right size.
*/
/* temporary buffer */
l_tile_height = gimp_tile_height ();
l_buf = g_new (guchar, l_tile_height * cinfo.output_width * cinfo.output_components);
l_rowbuf = g_new (guchar*, l_tile_height);
for (l_idx = 0; l_idx < l_tile_height; l_idx++)
{
l_rowbuf[l_idx] = l_buf + cinfo.output_width * cinfo.output_components * l_idx;
}
/* Check if jpeg file has one component (a channel cant have more than one)
*/
if(cinfo.output_components != 1)
{
fprintf(stderr, "XJT: cant load RGB layer %s into GRAY Image\n", filename);
fclose (infile);
return -1;
}
if(drawable_id < 0)
{
l_drawable_id = gimp_channel_new (image_id,
channel_name,
cinfo.output_width,
cinfo.output_height,
channel_opacity,
&l_color);
if(l_drawable_id < 0)
{
fprintf(stderr, "XJT: cant create new channel\n");
fclose (infile);
return -1;
}
}
else
{
l_drawable_id = drawable_id; /* overwrite the given drawable */
}
l_drawable = gimp_drawable_get (l_drawable_id);
if((l_drawable->width != cinfo.output_width)
|| (l_drawable->height != cinfo.output_height)
|| (l_drawable->bpp != cinfo.output_components) )
{
fprintf(stderr, "XJT: cant load-overwrite drawable (size missmatch)\n");
fclose (infile);
return -1;
}
gimp_pixel_rgn_init (&l_pixel_rgn, l_drawable, 0, 0, l_drawable->width, l_drawable->height, TRUE, FALSE);
/* Step 6: while (scan lines remain to be read) */
/* jpeg_read_scanlines(...); */
/* Here we use the library's state variable cinfo.output_scanline as the
* loop counter, so that we don't have to keep track ourselves.
*/
while (cinfo.output_scanline < cinfo.output_height)
{
l_start = cinfo.output_scanline;
l_end = cinfo.output_scanline + l_tile_height;
l_end = MIN (l_end, cinfo.output_height);
l_scanlines = l_end - l_start;
for (l_idx = 0; l_idx < l_scanlines; l_idx++)
{
jpeg_read_scanlines (&cinfo, (JSAMPARRAY) &l_rowbuf[l_idx], 1);
}
gimp_pixel_rgn_set_rect (&l_pixel_rgn, l_buf, 0, l_start, l_drawable->width, l_scanlines);
gimp_progress_update ((double) cinfo.output_scanline / (double) cinfo.output_height);
}
/* Step 7: Finish decompression */
jpeg_finish_decompress (&cinfo);
/* We can ignore the return value since suspension is not possible
* with the stdio data source.
*/
/* Step 8: Release JPEG decompression object */
/* This is an important step since it will release a good deal of memory. */
jpeg_destroy_decompress (&cinfo);
/* free up the temporary buffers */
g_free (l_rowbuf);
g_free (l_buf);
/* After finish_decompress, we can close the input file.
* Here we postpone it until after no more JPEG errors are possible,
* so as to simplify the setjmp error logic above. (Actually, I don't
* think that jpeg_destroy can do an error exit, but why assume anything...)
*/
fclose (infile);
/* At this point you may want to check to see whether any corrupt-data
* warnings occurred (test whether jerr.num_warnings is nonzero).
*/
/* Tell the GIMP to display the image.
*/
/* gimp_drawable_flush (l_drawable); */
return (l_drawable_id);
} /* end xjpg_load_channel */
/* ============================================================================
* xjpg_save_drawable
* save as drawable as jpeg file depending on save_mode:
* - save the drawable without alpha channel.
* (optional clear full transparent pixels to 0,
* resulting in better compression)
* - save the alpha channel
* ============================================================================
*/
gint
xjpg_save_drawable (char *filename,
gint32 image_ID,
gint32 drawable_ID,
gint save_mode,
t_JpegSaveVals *jsvals)
{
GimpPixelRgn pixel_rgn;
GimpDrawable *drawable;
GimpImageType drawable_type;
struct jpeg_compress_struct cinfo;
struct my_error_mgr jerr;
FILE * volatile outfile;
guchar *temp, *t;
guchar *data;
guchar *src, *s;
int has_alpha;
int rowstride, yend;
int i, j;
int alpha_offset;
guchar alpha_byte;
guchar volatile l_alpha_sum;
alpha_offset = 0;
has_alpha = 0;
src = NULL;
temp = NULL;
data = NULL;
l_alpha_sum = 0xff;
drawable = gimp_drawable_get (drawable_ID);
drawable_type = gimp_drawable_type (drawable_ID);
switch (drawable_type)
{
case GIMP_RGB_IMAGE:
case GIMP_GRAY_IMAGE:
if(save_mode == JSVM_ALPHA)
return FALSE; /* there is no alpha to save */
break;
case GIMP_RGBA_IMAGE:
case GIMP_GRAYA_IMAGE:
break;
case GIMP_INDEXED_IMAGE:
/*g_message ("jpeg: cannot operate on indexed color images");*/
return FALSE;
break;
default:
/*g_message ("jpeg: cannot operate on unknown image types");*/
return FALSE;
break;
}
gimp_pixel_rgn_init (&pixel_rgn, drawable, 0, 0, drawable->width, drawable->height, FALSE, FALSE);
/* Step 1: allocate and initialize JPEG compression object */
/* We have to set up the error handler first, in case the initialization
* step fails. (Unlikely, but it could happen if you are out of memory.)
* This routine fills in the contents of struct jerr, and returns jerr's
* address which we place into the link field in cinfo.
*/
cinfo.err = jpeg_std_error (&jerr.pub);
jerr.pub.error_exit = my_error_exit;
outfile = NULL;
/* Establish the setjmp return context for my_error_exit to use. */
if (setjmp (jerr.setjmp_buffer))
{
/* If we get here, the JPEG code has signaled an error.
* We need to clean up the JPEG object, close the input file, and return.
*/
jpeg_destroy_compress (&cinfo);
if (outfile)
fclose (outfile);
if (drawable)
gimp_drawable_detach (drawable);
return FALSE;
}
/* Now we can initialize the JPEG compression object. */
jpeg_create_compress (&cinfo);
/* Step 2: specify data destination (eg, a file) */
/* Note: steps 2 and 3 can be done in either order. */
/* Here we use the library-supplied code to send compressed data to a
* stdio stream. You can also write your own code to do something else.
* VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
* requires it in order to write binary files.
*/
if ((outfile = fopen (filename, "wb")) == NULL)
{
g_message ("can't open %s\n", filename);
return FALSE;
}
jpeg_stdio_dest (&cinfo, outfile);
/* Get the input image and a pointer to its data.
*/
switch (drawable_type)
{
case GIMP_RGB_IMAGE:
case GIMP_GRAY_IMAGE:
/* # of color components per pixel */
cinfo.input_components = drawable->bpp;
has_alpha = 0;
alpha_offset = 0;
break;
case GIMP_RGBA_IMAGE:
case GIMP_GRAYA_IMAGE:
if(save_mode == JSVM_ALPHA)
{
cinfo.input_components = 1;
}
else
{
/* # of color components per pixel (minus the GIMP alpha channel) */
cinfo.input_components = drawable->bpp - 1;
}
alpha_offset = drawable->bpp -1;
has_alpha = 1;
break;
default:
return FALSE;
break;
}
/* Step 3: set parameters for compression */
/* First we supply a description of the input image.
* Four fields of the cinfo struct must be filled in:
*/
/* image width and height, in pixels */
cinfo.image_width = drawable->width;
cinfo.image_height = drawable->height;
/* colorspace of input image */
cinfo.in_color_space = ( (save_mode != JSVM_ALPHA) &&
(drawable_type == GIMP_RGB_IMAGE ||
drawable_type == GIMP_RGBA_IMAGE))
? JCS_RGB : JCS_GRAYSCALE;
/* Now use the library's routine to set default compression parameters.
* (You must set at least cinfo.in_color_space before calling this,
* since the defaults depend on the source color space.)
*/
jpeg_set_defaults (&cinfo);
/* Now you can set any non-default parameters you wish to.
* Here we just illustrate the use of quality (quantization table) scaling:
*/
jpeg_set_quality (&cinfo, (int) (jsvals->quality * 100), TRUE /* limit to baseline-JPEG values */);
cinfo.smoothing_factor = (int) (jsvals->smoothing * 100);
cinfo.optimize_coding = jsvals->optimize;
/* Step 4: Start compressor */
/* TRUE ensures that we will write a complete interchange-JPEG file.
* Pass TRUE unless you are very sure of what you're doing.
*/
jpeg_start_compress (&cinfo, TRUE);
/* Step 5: while (scan lines remain to be written) */
/* jpeg_write_scanlines(...); */
/* Here we use the library's state variable cinfo.next_scanline as the
* loop counter, so that we don't have to keep track ourselves.
* To keep things simple, we pass one scanline per call; you can pass
* more if you wish, though.
*/
/* JSAMPLEs per row in image_buffer */
rowstride = drawable->bpp * drawable->width;
temp = (guchar *) g_malloc (cinfo.image_width * cinfo.input_components);
data = (guchar *) g_malloc (rowstride * gimp_tile_height ());
src = data;
while (cinfo.next_scanline < cinfo.image_height)
{
if ((cinfo.next_scanline % gimp_tile_height ()) == 0)
{
yend = cinfo.next_scanline + gimp_tile_height ();
yend = MIN (yend, cinfo.image_height);
gimp_pixel_rgn_get_rect (&pixel_rgn, data, 0, cinfo.next_scanline, cinfo.image_width,
(yend - cinfo.next_scanline));
src = data;
}
t = temp;
s = src;
i = cinfo.image_width;
switch(save_mode)
{
case JSVM_DRAWABLE:
if(jsvals->clr_transparent)
{
/* save drawable (clear pixels where alpha is full transparent) */
while (i--)
{
alpha_byte = s[cinfo.input_components];
for (j = 0; j < cinfo.input_components; j++)
{
if(alpha_byte != 0) { *t++ = *s++; }
else { *t++ = 0; s++; }
}
if (has_alpha) /* ignore alpha channel */
{
s++;
}
}
}
else
{
/* save the drawable as it is (ignore alpha channel) */
while (i--)
{
for (j = 0; j < cinfo.input_components; j++)
{
*t++ = *s++;
}
if (has_alpha) /* ignore alpha channel */
{
s++;
}
}
}
break;
case JSVM_ALPHA:
/* save the drawable's alpha cahnnel */
while (i--)
{
s += alpha_offset;
l_alpha_sum &= (*s); /* check all alpha bytes for full opacity */
*t++ = *s++;
}
break;
}
src += rowstride;
jpeg_write_scanlines (&cinfo, (JSAMPARRAY) &temp, 1);
if ((cinfo.next_scanline % 5) == 0)
gimp_progress_update ((double) cinfo.next_scanline / (double) cinfo.image_height);
}
/* Step 6: Finish compression */
jpeg_finish_compress (&cinfo);
/* After finish_compress, we can close the output file. */
fclose (outfile);
if((save_mode == JSVM_ALPHA) && (l_alpha_sum == 0xff))
{
/* all bytes in the alpha channel are set to 0xff
* == full opaque image. We can remove the file
* to save diskspace
*/
remove(filename);
}
/* Step 7: release JPEG compression object */
/* This is an important step since it will release a good deal of memory. */
jpeg_destroy_compress (&cinfo);
/* free the temporary buffer */
g_free (temp);
g_free (data);
gimp_drawable_detach (drawable);
return TRUE;
} /* end xjpg_save_drawable */
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