New function to create a blank pixbuf.

1999-10-27  Havoc Pennington  <hp@pobox.com>

* src/gdk-pixbuf.c (gdk_pixbuf_new): New function to create a
blank pixbuf.

* src/gdk-pixbuf-loader.c (gdk_pixbuf_loader_write): Check all
three progressive load funcs are non-NULL, rather than checking
begin_load three times. Also, check whether begin_load returns
NULL on failure.

gdk-pixbuf/gdk-pixbuf-loader.c

@@ -240,14 +240,19 @@ gdk_pixbuf_loader_write (GdkPixbufLoader *loader, gchar *buf, gint count)
 			if (priv->image_module == NULL) {
 				return FALSE;
 			} else if ((priv->image_module->begin_load == NULL) ||
-				   (priv->image_module->begin_load == NULL) ||
-				   (priv->image_module->begin_load == NULL) ||
-				   (priv->image_module->begin_load == NULL)) {
+				   (priv->image_module->stop_load == NULL) ||
+				   (priv->image_module->load_increment == NULL)) {
 				g_warning ("module %s does not support incremental loading.\n", priv->image_module->module_name);
 				return FALSE;
 			} else {
 				g_print ("module loaded: name is %s\n", priv->image_module->module_name);
 				priv->context = (priv->image_module->begin_load) (gdk_pixbuf_loader_prepare, loader);
+
+                                if (priv->context == NULL) {
+                                        g_warning("Failed to begin progressive load");
+                                        return FALSE;
+                                }
+                                
 				retval = (priv->image_module->load_increment) (priv->context, priv->buf, 128);
 
 				/* if we had more then 128 bytes total, we want to send the rest of the buffer */

gdk-pixbuf/gdk-pixbuf.c

@@ -99,3 +99,64 @@ gdk_pixbuf_new_from_art_pixbuf (ArtPixBuf *art_pixbuf)
 
 	return pixbuf;
 }
+
+/**
+ * gdk_pixbuf_new:
+ * @art_pixbuf: A libart pixbuf.
+ *
+ * Creates a &GdkPixbuf; magically sets the ArtPixFormat, rowstride, and creates
+ * the buffer. Use gdk_pixbuf_new_from_data() to do things manually.
+ *
+ * Return value: A newly-created &GdkPixbuf structure with a reference count of
+ * 1. Somewhat oddly, returns NULL if it can't allocate the buffer; this unusual
+ * behavior is needed because images can be very large.
+ **/
+GdkPixbuf *
+gdk_pixbuf_new (gboolean has_alpha, int width, int height)
+{
+        GdkPixbuf *pixbuf;
+
+	g_return_val_if_fail (width > 0, NULL);
+        g_return_val_if_fail (height > 0, NULL);
+
+	pixbuf = g_new (GdkPixbuf, 1);
+	pixbuf->ref_count = 1;
+        
+        if (has_alpha) {
+                art_u8* pixels;
+                int rowstride;
+
+                /* FIXME, pick an optimal stride */                
+                rowstride = 4*width;
+
+                pixels = art_alloc(rowstride*height);
+
+                if (pixels == NULL) {
+                        g_free(pixbuf);
+                        return NULL;
+                }
+                
+                pixbuf->art_pixbuf = art_pixbuf_new_rgba(pixels, width, height, rowstride);
+        } else {
+                art_u8* pixels;
+                int rowstride;
+
+                /* FIXME, pick an optimal stride */
+                rowstride = 3*width;
+
+                pixels = art_alloc(rowstride*height);
+
+                if (pixels == NULL) {
+                        g_free(pixbuf);
+                        return NULL;
+                }
+
+                pixbuf->art_pixbuf = art_pixbuf_new_rgb(pixels, width, height, rowstride);
+        }
+                
+	return pixbuf;
+
+
+}
+
+

gdk-pixbuf/gdk-pixbuf.h

@@ -59,6 +59,9 @@ void gdk_pixbuf_unref (GdkPixbuf *pixbuf);
 
 GdkPixbuf *gdk_pixbuf_new_from_art_pixbuf (ArtPixBuf *art_pixbuf);
 
+/* Create a "blank" pixbuf with an optimal rowstride and a new buffer */
+GdkPixbuf *gdk_pixbuf_new (gboolean has_alpha, int width, int height);
+
 /* Simple loading */
 
 GdkPixbuf *gdk_pixbuf_new_from_file (const char *filename);

gtk/gdk-pixbuf-loader.c

@@ -240,14 +240,19 @@ gdk_pixbuf_loader_write (GdkPixbufLoader *loader, gchar *buf, gint count)
 			if (priv->image_module == NULL) {
 				return FALSE;
 			} else if ((priv->image_module->begin_load == NULL) ||
-				   (priv->image_module->begin_load == NULL) ||
-				   (priv->image_module->begin_load == NULL) ||
-				   (priv->image_module->begin_load == NULL)) {
+				   (priv->image_module->stop_load == NULL) ||
+				   (priv->image_module->load_increment == NULL)) {
 				g_warning ("module %s does not support incremental loading.\n", priv->image_module->module_name);
 				return FALSE;
 			} else {
 				g_print ("module loaded: name is %s\n", priv->image_module->module_name);
 				priv->context = (priv->image_module->begin_load) (gdk_pixbuf_loader_prepare, loader);
+
+                                if (priv->context == NULL) {
+                                        g_warning("Failed to begin progressive load");
+                                        return FALSE;
+                                }
+                                
 				retval = (priv->image_module->load_increment) (priv->context, priv->buf, 128);
 
 				/* if we had more then 128 bytes total, we want to send the rest of the buffer */