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Added first cut at progressive jpeg loading. Currently does not handle
999-10-29 Michael Fulbright <drmike@redhat.com>
* src/io-jpeg.c: Added first cut at progressive jpeg loading.
Currently does not handle either progressive jpeg files (jpeg
files with multiple scans at different quality settings), but
I plan on adding this support soon. These are fairly rare in
my experience, so it shouldn't slow people down too much.
Grayscale jpegs also don't work but that should be easy to fix.
This commit is contained in:
Michael Fulbright
Michael Fulbright
parent
a3fd5f8d9a
commit
a4a876d70e
@ -2,9 +2,12 @@
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*
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* Copyright (C) 1999 Michael Zucchi
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* Copyright (C) 1999 The Free Software Foundation
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*
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* Progressive loading code Copyright (C) 1999 Red Hat, Inc.
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*
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* Authors: Michael Zucchi <zucchi@zedzone.mmc.com.au>
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* Federico Mena-Quintero <federico@gimp.org>
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* Michael Fulbright <drmike@redhat.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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@ -22,20 +25,74 @@
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* Boston, MA 02111-1307, USA.
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*/
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/*
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Progressive file loading notes (10/29/199) <drmike@redhat.com>...
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These are issues I know of and will be dealing with shortly:
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- Currently does not handle progressive jpegs - this
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requires a change in the way image_load_increment () calls
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libjpeg. Progressive jpegs are rarer but I will add this
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support asap.
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- gray images are not properly loaded
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- error handling is not as good as it should be
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*/
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#include <config.h>
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#include <stdio.h>
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#include <setjmp.h>
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#include <jpeglib.h>
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#include "gdk-pixbuf.h"
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#include "gdk-pixbuf-io.h"
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/* we are a "source manager" as far as libjpeg is concerned */
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typedef struct {
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struct jpeg_source_mgr pub; /* public fields */
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JOCTET * buffer; /* start of buffer */
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gboolean start_of_file; /* have we gotten any data yet? */
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long skip_next; /* number of bytes to skip next read */
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} my_source_mgr;
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typedef my_source_mgr * my_src_ptr;
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/* error handler data */
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struct error_handler_data {
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struct jpeg_error_mgr pub;
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sigjmp_buf setjmp_buffer;
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};
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/* progressive loader context */
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typedef struct {
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ModulePreparedNotifyFunc notify_func;
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gpointer notify_user_data;
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GdkPixbuf *pixbuf;
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guchar *dptr; /* current position in pixbuf */
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gboolean did_prescan; /* are we in image data yet? */
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gboolean got_header; /* have we loaded jpeg header? */
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gboolean src_initialized;/* TRUE when jpeg lib initialized */
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struct jpeg_decompress_struct cinfo;
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struct error_handler_data jerr;
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} JpegProgContext;
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#define JPEG_PROG_BUF_SIZE 4096
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GdkPixbuf *image_load (FILE *f);
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gpointer image_begin_load (ModulePreparedNotifyFunc func, gpointer user_data);
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void image_stop_load (gpointer context);
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gboolean image_load_increment(gpointer context, guchar *buf, guint size);
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static void
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fatal_error_handler (j_common_ptr cinfo)
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{
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@ -57,11 +114,42 @@ free_buffer (gpointer user_data, gpointer data)
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free (data);
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}
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/* explode gray image data from jpeg library into rgb components in pixbuf */
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static void
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explode_gray_into_buf (struct jpeg_decompress_struct *cinfo,
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guchar **lines)
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{
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gint i, j;
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guint w;
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g_return_if_fail (cinfo != NULL);
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g_return_if_fail (cinfo->output_components == 1);
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/* Expand grey->colour. Expand from the end of the
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* memory down, so we can use the same buffer.
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*/
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w = cinfo->image_width;
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for (i = cinfo->rec_outbuf_height - 1; i >= 0; i--) {
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guchar *from, *to;
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from = lines[i] + w - 1;
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to = lines[i] + (w - 1) * 3;
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for (j = w - 1; j >= 0; j--) {
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to[0] = from[0];
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to[1] = from[1];
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to[2] = from[2];
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to -= 3;
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from--;
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}
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}
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}
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/* Shared library entry point */
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GdkPixbuf *
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image_load (FILE *f)
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{
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int w, h, i, j;
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int w, h, i;
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guchar *pixels = NULL;
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guchar *dptr;
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guchar *lines[4]; /* Used to expand rows, via rec_outbuf_height, from the header file:
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@ -114,24 +202,9 @@ image_load (FILE *f)
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}
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jpeg_read_scanlines (&cinfo, lines, cinfo.rec_outbuf_height);
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if (cinfo.output_components == 1) {
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/* Expand grey->colour. Expand from the end of the
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* memory down, so we can use the same buffer.
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*/
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for (i = cinfo.rec_outbuf_height - 1; i >= 0; i--) {
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guchar *from, *to;
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from = lines[i] + w - 1;
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to = lines[i] + w * 3 - 3;
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for (j = w - 1; j >= 0; j--) {
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to[0] = from[0];
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to[1] = from[0];
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to[2] = from[0];
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to -= 3;
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from--;
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}
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}
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}
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if (cinfo.output_components == 1)
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explode_gray_into_buf (&cinfo, lines);
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}
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jpeg_finish_decompress (&cinfo);
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@ -143,3 +216,289 @@ image_load (FILE *f)
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return pixbuf;
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}
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/**** Progressive image loading handling *****/
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/* these routines required because we are acting as a source manager for */
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/* libjpeg. */
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static void
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init_source (j_decompress_ptr cinfo)
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{
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my_src_ptr src = (my_src_ptr) cinfo->src;
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src->start_of_file = TRUE;
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src->skip_next = 0;
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}
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static void
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term_source (j_decompress_ptr cinfo)
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{
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/* XXXX - probably should scream something has happened */
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}
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/* for progressive loading (called "I/O Suspension" by libjpeg docs) */
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/* we do nothing except return "FALSE" */
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static boolean
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fill_input_buffer (j_decompress_ptr cinfo)
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{
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return FALSE;
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}
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static void
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skip_input_data (j_decompress_ptr cinfo, long num_bytes)
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{
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my_src_ptr src = (my_src_ptr) cinfo->src;
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long num_can_do;
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/* move as far as we can into current buffer */
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/* then set skip_next to catch the rest */
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if (num_bytes > 0) {
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num_can_do = MIN (src->pub.bytes_in_buffer, num_bytes);
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src->pub.next_input_byte += (size_t) num_can_do;
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src->pub.bytes_in_buffer -= (size_t) num_can_do;
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src->skip_next = num_bytes - num_can_do;
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}
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}
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/*
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* func - called when we have pixmap created (but no image data)
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* user_data - passed as arg 1 to func
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* return context (opaque to user)
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*/
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gpointer
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image_begin_load (ModulePreparedNotifyFunc func, gpointer user_data)
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{
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JpegProgContext *context;
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my_source_mgr *src;
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context = g_new (JpegProgContext, 1);
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context->notify_func = func;
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context->notify_user_data = user_data;
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context->pixbuf = NULL;
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context->got_header = FALSE;
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context->did_prescan = FALSE;
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context->src_initialized = FALSE;
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/* create libjpeg structures */
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jpeg_create_decompress (&context->cinfo);
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context->cinfo.src = (struct jpeg_source_mgr *) g_new (my_source_mgr, 1);
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src = (my_src_ptr) context->cinfo.src;
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src->buffer = g_malloc (JPEG_PROG_BUF_SIZE);
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context->cinfo.err = jpeg_std_error (&context->jerr.pub);
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src = (my_src_ptr) context->cinfo.src;
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src->pub.init_source = init_source;
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src->pub.fill_input_buffer = fill_input_buffer;
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src->pub.skip_input_data = skip_input_data;
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src->pub.resync_to_restart = jpeg_resync_to_restart;
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src->pub.term_source = term_source;
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src->pub.bytes_in_buffer = 0;
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src->pub.next_input_byte = NULL;
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return (gpointer) context;
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}
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/*
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* context - returned from image_begin_load
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*
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* free context, unref gdk_pixbuf
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*/
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void
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image_stop_load (gpointer data)
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{
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JpegProgContext *context = (JpegProgContext *) data;
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g_return_if_fail (context != NULL);
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/* XXXX - is this all I have to do to cleanup? */
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if (context->pixbuf)
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gdk_pixbuf_unref (context->pixbuf);
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if (context->cinfo.src) {
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my_src_ptr src = (my_src_ptr) context->cinfo.src;
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if (src->buffer)
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g_free (src->buffer);
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g_free (src);
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}
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jpeg_finish_decompress(&context->cinfo);
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jpeg_destroy_decompress(&context->cinfo);
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g_free (context);
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}
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/*
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* context - from image_begin_load
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* buf - new image data
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* size - length of new image data
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*
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* append image data onto inrecrementally built output image
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*/
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gboolean
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image_load_increment (gpointer data, guchar *buf, guint size)
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{
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JpegProgContext *context = (JpegProgContext *)data;
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struct jpeg_decompress_struct *cinfo;
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my_src_ptr src;
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guint num_left, num_copy;
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guchar *nextptr;
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g_return_val_if_fail (context != NULL, FALSE);
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g_return_val_if_fail (buf != NULL, FALSE);
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src = (my_src_ptr) context->cinfo.src;
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cinfo = &context->cinfo;
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/* skip over data if requested, handle unsigned int sizes cleanly */
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/* only can happen if we've already called jpeg_get_header once */
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if (context->src_initialized && src->skip_next) {
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if (src->skip_next > size) {
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src->skip_next -= size;
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return TRUE;
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} else {
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num_left = size - src->skip_next;
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src->skip_next = 0;
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}
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} else {
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num_left = size;
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}
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while (num_left > 0) {
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/* copy as much data into buffer as possible */
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num_copy = MIN (JPEG_PROG_BUF_SIZE - src->pub.bytes_in_buffer,
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size);
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if (num_copy == 0)
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g_assert ("Buffer overflow!\n");
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nextptr = src->buffer + src->pub.bytes_in_buffer;
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memcpy (nextptr, buf, num_copy);
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if (src->pub.next_input_byte == NULL ||
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src->pub.bytes_in_buffer == 0)
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src->pub.next_input_byte = src->buffer;
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src->pub.bytes_in_buffer += num_copy;
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num_left -= num_copy;
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/* try to load jpeg header */
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/* XXXX - bad - assume we always have enough data */
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/* to determine header info in first */
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/* invocation of this function */
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if (!context->got_header) {
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int rc;
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rc = jpeg_read_header (cinfo, TRUE);
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context->src_initialized = TRUE;
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if (rc == JPEG_SUSPENDED)
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continue;
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context->got_header = TRUE;
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if (jpeg_has_multiple_scans (cinfo)) {
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g_print ("io-jpeg.c: Does not currently "
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"support progressive jpeg files.\n");
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return FALSE;
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}
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context->pixbuf = gdk_pixbuf_new(ART_PIX_RGB,
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/*have_alpha*/ FALSE,
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8,
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cinfo->image_width,
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cinfo->image_height);
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if (context->pixbuf == NULL) {
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/* Failed to allocate memory */
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g_assert ("Couldn't allocate gdkpixbuf\n");
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}
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/* Use pixbuf pixel buffer - BUT NOT SURE */
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/* we handle rowstride correctly!!!! */
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context->dptr = context->pixbuf->art_pixbuf->pixels;
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/* Notify the client that we are ready to go */
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if (context->notify_func)
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(* context->notify_func) (context->pixbuf,
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context->notify_user_data);
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src->start_of_file = FALSE;
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} else if (!context->did_prescan) {
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int rc;
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/* start decompression */
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rc = jpeg_start_decompress (cinfo);
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cinfo->do_fancy_upsampling = FALSE;
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cinfo->do_block_smoothing = FALSE;
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if (rc == JPEG_SUSPENDED)
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continue;
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context->did_prescan = TRUE;
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} else {
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/* we're decompressing so feed jpeg lib scanlines */
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guchar *lines[4];
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guchar **lptr;
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guchar *rowptr;
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gint nlines, i;
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gint start_scanline;
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/* THIS COULD BE BROKEN */
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/* Assumes rowstride of gdkpixbuf pixel buffer */
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/* is same as incoming jpeg data! */
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while (cinfo->output_scanline < cinfo->output_height) {
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start_scanline = cinfo->output_scanline;
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lptr = lines;
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rowptr = context->dptr;
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for (i=0; i < cinfo->rec_outbuf_height; i++) {
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*lptr++ = rowptr;
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rowptr += cinfo->image_width * 3;
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}
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nlines = jpeg_read_scanlines (cinfo, lines,
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cinfo->rec_outbuf_height);
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if (nlines == 0)
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break;
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/* handle gray */
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if (cinfo->output_components == 1)
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explode_gray_into_buf (cinfo, lines);
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context->dptr += nlines * cinfo->image_width * 3;
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#ifdef DEBUG_JPEG_PROGRESSIVE
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if (start_scanline != cinfo->output_scanline)
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g_print("jpeg: Input pass=%2d, next input scanline=%3d,"
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" emitted %3d - %3d\n",
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cinfo->input_scan_number, cinfo->input_iMCU_row * 16,
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start_scanline, cinfo->output_scanline - 1);
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g_print ("Scanline %d of %d - ",
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cinfo->output_scanline,
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cinfo->output_height);
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/* g_print ("rec_height %d -", cinfo->rec_outbuf_height); */
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g_print ("Processed %d lines - bytes left = %d\n",
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nlines, cinfo->src->bytes_in_buffer);
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#endif
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}
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}
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}
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return TRUE;
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}
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