[lasem] svg_view: test cairo_pattern_get_surface return value

[Emmanuel Pacaud <emmanuel src gnome org>]

commit dc3d5115d68759cafe19ebe3a4ec945b9f85c45e
Author: Emmanuel Pacaud <emmanuel gnome org>
Date:   Sun Jul 19 14:14:11 2015 +0200

    svg_view: test cairo_pattern_get_surface return value
    
    It looks like surface may be not NULL even if the result is not success.

 src/lsmsvgview.c |   39 ++++++++++++++++++++-------------------
 1 files changed, 20 insertions(+), 19 deletions(-)
---
diff --git a/src/lsmsvgview.c b/src/lsmsvgview.c
index 04e501a..e9d9985 100644
--- a/src/lsmsvgview.c
+++ b/src/lsmsvgview.c
@@ -1774,23 +1774,25 @@ lsm_svg_view_pop_mask (LsmSvgView *view)
                cairo_pop_group_to_source (cairo);
                if (view->pattern_data->pattern != NULL) {
                        cairo_surface_t *surface;
-                       int width, height, row, i, stride;
-                       unsigned char *pixels;
-
-                       cairo_pattern_get_surface (view->pattern_data->pattern, &surface);
-                       pixels = cairo_image_surface_get_data (surface);
-                       height = cairo_image_surface_get_height (surface);
-                       width = cairo_image_surface_get_width (surface);
-                       stride = cairo_image_surface_get_stride (surface);
-
-                       for (row = 0; row < height; row++) {
-                               guint8 *row_data = (pixels + (row * stride));
-                               for (i = 0; i < width; i++) {
-                                       guint32 *pixel = (guint32 *) row_data + i;
-                                       *pixel = ((((*pixel & 0x00ff0000) >> 16) * 13817 +
-                                                  ((*pixel & 0x0000ff00) >> 8) * 46518 +
-                                                  ((*pixel & 0x000000ff)) * 4688) * 0xff
-                                                 /* * opacity */);
+
+                       if (cairo_pattern_get_surface (view->pattern_data->pattern, &surface) == 
CAIRO_STATUS_SUCCESS) {
+                               int width, height, row, i, stride;
+                               unsigned char *pixels;
+
+                               pixels = cairo_image_surface_get_data (surface);
+                               height = cairo_image_surface_get_height (surface);
+                               width = cairo_image_surface_get_width (surface);
+                               stride = cairo_image_surface_get_stride (surface);
+
+                               for (row = 0; row < height; row++) {
+                                       guint8 *row_data = (pixels + (row * stride));
+                                       for (i = 0; i < width; i++) {
+                                               guint32 *pixel = (guint32 *) row_data + i;
+                                               *pixel = ((((*pixel & 0x00ff0000) >> 16) * 13817 +
+                                                          ((*pixel & 0x0000ff00) >> 8) * 46518 +
+                                                          ((*pixel & 0x000000ff)) * 4688) * 0xff
+                                                         /* * opacity */);
+                                       }
                                }
                        }
 
@@ -1881,8 +1883,7 @@ lsm_svg_view_pop_filter (LsmSvgView *view)
 
        if (LSM_IS_SVG_FILTER_ELEMENT (filter_element) &&
            view->pattern_data->pattern != NULL) {
-               cairo_pattern_get_surface (view->pattern_data->pattern, &surface);
-               if (surface != NULL) {
+               if (cairo_pattern_get_surface (view->pattern_data->pattern, &surface) == 
CAIRO_STATUS_SUCCESS) {
                        cairo_matrix_t matrix;
                        LsmBox subregion;