Added some assertions

src/gfx/generated_image.cpp

@@ -84,6 +84,7 @@ Image BlankImage::generate(const Options& opt) const {
   int w = max(1, opt.width >= 0  ? opt.width  : opt.height);
   int h = max(1, opt.height >= 0 ? opt.height : opt.width);
   Image img(w, h);
+  assert(img.Ok());
   img.InitAlpha();
   memset(img.GetAlpha(), 0, w * h);
   return img;

src/gfx/mask_image.cpp

@@ -134,6 +134,7 @@ void AlphaMask::convexHull(vector<wxPoint>& points) const {
 
 Image AlphaMask::colorImage(const Color& color) const {
   Image image(size.x, size.y);
+  assert(image.Ok());
   fill_image(image, color);
   setAlpha(image);
   return image;

src/render/value/choice.cpp

@@ -86,6 +86,7 @@ void draw_choice_viewer(RotatedDC& dc, ValueViewer& viewer, ChoiceStyle& style,
         dc.DrawPreRotatedBitmap(bitmap,rect);
       } else {
         // use combine mode
+        assert(image.Ok());
         dc.DrawPreRotatedImage(image,rect,combine);
       }
       margin = size.width + 2;

src/script/image.cpp

@@ -89,6 +89,7 @@ template <> void GetDefaultMember::handle(const ScriptableImage& s) {
 void CachedScriptableImage::generateCached(const GeneratedImage::Options& options,
                                          CachedScriptableMask* mask,
                                          ImageCombine* combine, wxBitmap* bitmap, wxImage* image, RealSize* size) {
+  assert(image && bitmap);
   // ready?
   if (!isReady()) {
     // error, return blank image
@@ -137,6 +138,7 @@ void CachedScriptableImage::generateCached(const GeneratedImage::Options& option
   const_cast<GeneratedImage::Options&>(options).angle = 0;
   // generate
   cached_i = generate(options);
+  assert(cached_i.Ok());
   const_cast<GeneratedImage::Options&>(options).angle = cached_angle = a;
   *size = cached_size = RealSize(options.width, options.height);
   if (mask) {
@@ -157,6 +159,7 @@ void CachedScriptableImage::generateCached(const GeneratedImage::Options& option
   } else {
     *image = cached_i;
   }
+  assert(image->Ok() || bitmap->Ok());
 }
 
 bool CachedScriptableImage::update(Context& ctx) {