Consolidate and quantize all transformations

This commit defers all outline transformations until rasterization stage.
Combined transformation is then quantized and used as bitmap key.
That should improve performance of slow animations.

Also caching of initial and stroked outlines and bitmaps is now separate
in preparation to proper error estimation for stroker stage.

Note that Z-clipping for perspective transformations is now done
differently compared to VSFilter. That clipping is mostly safety feature
to protect from overflows and divisions by zero and is almost never
triggered in real-world subtitles.

1 files changed, 10 insertions, 4 deletions

diff --git a/libass/ass_render.h b/libass/ass_render.h
index 539d619..f8d84f9 100644
--- a/libass/ass_render.h
+++ b/libass/ass_render.h
@@ -113,6 +113,10 @@ typedef struct {
     CompositeHashValue *image;
 } CombinedBitmapInfo;
 
+typedef struct {
+    ASS_DVector scale, offset;
+} ASS_Transform;
+
 // describes a glyph
 // GlyphInfo and TextInfo are used for text centering and word-wrapping operations
 typedef struct glyph_info {
@@ -130,8 +134,9 @@ typedef struct glyph_info {
     char *drawing_text;
     int drawing_scale;
     int drawing_pbo;
-    ASS_Outline *outline;
-    ASS_Outline *border[2];
+    OutlineHashValue *outline, *border;
+    ASS_Transform outline_transform;
+    ASS_Transform border_transform;
     ASS_Rect bbox;
     ASS_Vector pos;
     ASS_Vector offset;
@@ -166,8 +171,9 @@ typedef struct glyph_info {
 
     int shape_run_id;
 
-    BitmapHashKey hash_key;
-    BitmapHashValue *image;
+    ASS_Vector shift;
+    ASS_Vector bitmap_advance;
+    BitmapHashValue *image, *image_o;
 
     // next glyph in this cluster
     struct glyph_info *next;