From 27d38660459971a039fbbe9ec95a1cec7470634b Mon Sep 17 00:00:00 2001
From: =?utf8?q?Kristian=20H=C3=B8gsberg?= <krh@bitplanet.net>
Date: Thu, 20 Oct 2011 13:11:12 -0400
Subject: [PATCH] cairo-util: Add helper to load jpeg files

---
 clients/cairo-util.c    | 54 +++++++++++++++++++++++++++++++++++++++++++++++++
 clients/cairo-util.h    |  3 +++
 clients/desktop-shell.c |  4 +++-
 configure.ac            |  8 ++++++++
 4 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/clients/cairo-util.c b/clients/cairo-util.c
index 184f58e..502f4b8 100644
--- a/clients/cairo-util.c
+++ b/clients/cairo-util.c
@@ -28,6 +28,8 @@
 #include <cairo.h>
 #include "cairo-util.h"
 
+#include <jpeglib.h>
+
 #define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
 
 void
@@ -286,3 +288,55 @@ rounded_rect(cairo_t *cr, int x0, int y0, int x1, int y1, int radius)
 	cairo_arc(cr, x0 + radius, y1 - radius, radius, M_PI / 2, M_PI);
 	cairo_close_path(cr);
 }
+
+cairo_surface_t *
+load_jpeg(const char *filename)
+{
+	struct jpeg_decompress_struct cinfo;
+	struct jpeg_error_mgr jerr;
+	FILE *fp;
+	int stride, i;
+	JSAMPLE *data, *rows[4];
+
+	cinfo.err = jpeg_std_error(&jerr);
+	jpeg_create_decompress(&cinfo);
+
+	fp = fopen(filename, "rb");
+	if (fp == NULL) {
+		fprintf(stderr, "can't open %s\n", filename);
+		return NULL;
+	}
+	jpeg_stdio_src(&cinfo, fp);
+
+	jpeg_read_header(&cinfo, TRUE);
+
+	cinfo.out_color_space = JCS_EXT_BGRX;
+	jpeg_start_decompress(&cinfo);
+
+	stride = cairo_format_stride_for_width(CAIRO_FORMAT_RGB24,
+					       cinfo.output_width);
+	data = malloc(stride * cinfo.output_height);
+	if (data == NULL) {
+		fprintf(stderr, "couldn't allocate image data\n");
+		return NULL;
+	}
+
+	while (cinfo.output_scanline < cinfo.output_height) {
+		for (i = 0; i < ARRAY_LENGTH(rows); i++, p += stride)
+			rows[i] = data + (cinfo.output_scanline + i) * stride;
+
+		jpeg_read_scanlines(&cinfo, rows, ARRAY_LENGTH(rows));
+	}
+
+	jpeg_finish_decompress(&cinfo);
+
+	fclose(fp);
+
+	jpeg_destroy_decompress(&cinfo);
+
+	return cairo_image_surface_create_for_data (data,
+						    CAIRO_FORMAT_RGB24,
+						    cinfo.output_width,
+						    cinfo.output_height,
+						    stride);
+}
diff --git a/clients/cairo-util.h b/clients/cairo-util.h
index e490b9f..07613ac 100644
--- a/clients/cairo-util.h
+++ b/clients/cairo-util.h
@@ -40,4 +40,7 @@ tile_source(cairo_t *cr, cairo_surface_t *surface,
 void
 rounded_rect(cairo_t *cr, int x0, int y0, int x1, int y1, int radius);
 
+cairo_surface_t *
+load_jpeg(const char *filename);
+
 #endif
diff --git a/clients/desktop-shell.c b/clients/desktop-shell.c
index 7ad6f02..016d720 100644
--- a/clients/desktop-shell.c
+++ b/clients/desktop-shell.c
@@ -32,6 +32,7 @@
 #include <linux/input.h>
 
 #include "wayland-client.h"
+#include "cairo-util.h"
 #include "window.h"
 
 #include <desktop-shell-client-protocol.h>
@@ -241,7 +242,7 @@ background_draw(struct window *window, int width, int height, const char *path)
 	cairo_paint(cr);
 
 	if (path) {
-		image = cairo_image_surface_create_from_png(path);
+		image = load_jpeg(path);
 		pattern = cairo_pattern_create_for_surface(image);
 		sx = (double) cairo_image_surface_get_width(image) / width;
 		sy = (double) cairo_image_surface_get_height(image) / height;
@@ -250,6 +251,7 @@ background_draw(struct window *window, int width, int height, const char *path)
 		cairo_set_source(cr, pattern);
 		cairo_pattern_destroy (pattern);
 		cairo_paint(cr);
+		cairo_surface_destroy(image);
 	}
 
 	cairo_destroy(cr);
diff --git a/configure.ac b/configure.ac
index f19c4e7..e278a1c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -113,6 +113,14 @@ if test x$enable_clients == xyes; then
   AS_IF([test "x$have_cairo_egl" = "xyes"],
         [AC_DEFINE([HAVE_CAIRO_EGL], [1], [Have cairo-egl])],
         [AC_MSG_WARN([Cairo-EGL not found - clients will use cairo image])])
+
+  AC_CHECK_LIB([jpeg], [jpeg_CreateDecompress], have_jpeglib=yes)
+  if test x$have_jpeglib == xyes; then
+    CLIENT_LIBS="$CLIENT_LIBS -ljpeg"
+  else
+    AC_ERROR([libjpeg not found])
+  fi
+
 fi
 
 AM_CONDITIONAL(HAVE_POPPLER, test "x$have_poppler" = "xyes")
-- 
2.7.4