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, 17 insertions, 45 deletions

diff --git a/libass/ass_cache_template.h b/libass/ass_cache_template.h
index 2bb0228..0c4ffdc 100644
--- a/libass/ass_cache_template.h
+++ b/libass/ass_cache_template.h
@@ -51,26 +51,14 @@
 
 
 // describes an outline bitmap
-START(outline_bitmap, outline_bitmap_hash_key)
+START(bitmap, bitmap_hash_key)
     GENERIC(OutlineHashValue *, outline)
-    GENERIC(int, frx) // signed 10.22
-    GENERIC(int, fry) // signed 10.22
-    GENERIC(int, frz) // signed 10.22
-    GENERIC(int, fax) // signed 16.16
-    GENERIC(int, fay) // signed 16.16
-    // shift vector that was added to glyph before applying rotation
-    // = 0, if frx = fry = frx = 0
-    // = (glyph base point) - (rotation origin), otherwise
-    GENERIC(int, shift_x)
-    GENERIC(int, shift_y)
-    VECTOR(advance) // subpixel shift vector
-END(OutlineBitmapHashKey)
-
-// describe a clip mask bitmap
-START(clip_bitmap, clip_bitmap_hash_key)
-    GENERIC(int, scale)
-    STRING(text)
-END(ClipMaskHashKey)
+    // quantized transform matrix
+    VECTOR(offset)
+    VECTOR(matrix_x)
+    VECTOR(matrix_y)
+    VECTOR(matrix_z)
+END(BitmapHashKey)
 
 START(glyph_metrics, glyph_metrics_hash_key)
     GENERIC(ASS_Font *, font)
@@ -79,25 +67,8 @@ START(glyph_metrics, glyph_metrics_hash_key)
     GENERIC(int, glyph_index)
 END(GlyphMetricsHashKey)
 
-// common outline data
-START(outline_common, outline_common_hash_key)
-    GENERIC(unsigned, scale_x) // 16.16
-    GENERIC(unsigned, scale_y) // 16.16
-    VECTOR(outline) // border width, 26.6
-    GENERIC(unsigned, border_style)
-    GENERIC(int, scale_fix)    // 16.16
-    GENERIC(int, advance)      // 26.6
-END(OutlineCommonKey)
-
 // describes an outline glyph
 START(glyph, glyph_hash_key)
-    GENERIC(unsigned, scale_x) // 16.16
-    GENERIC(unsigned, scale_y) // 16.16
-    VECTOR(outline) // border width, 26.6
-    GENERIC(unsigned, border_style)
-    GENERIC(int, scale_fix)    // 16.16
-    GENERIC(int, advance)      // 26.6
-
     GENERIC(ASS_Font *, font)
     GENERIC(double, size) // font size
     GENERIC(int, face_index)
@@ -109,18 +80,19 @@ END(GlyphHashKey)
 
 // describes an outline drawing
 START(drawing, drawing_hash_key)
-    GENERIC(unsigned, scale_x) // 16.16
-    GENERIC(unsigned, scale_y) // 16.16
-    VECTOR(outline) // border width, 26.6
-    GENERIC(unsigned, border_style)
-    GENERIC(int, scale_fix)    // 16.16
-    GENERIC(int, advance)      // 26.6
-
-    GENERIC(int, pbo)
-    GENERIC(int, scale)
     STRING(text)
 END(DrawingHashKey)
 
+// describes an offset outline
+START(border, border_hash_key)
+    GENERIC(OutlineHashValue *, outline)
+    // outline is scaled by 2^scale_ord_x|y before stroking
+    // to keep stoker error in allowable range
+    GENERIC(int, scale_ord_x)
+    GENERIC(int, scale_ord_y)
+    VECTOR(border)  // border size in STROKER_ACCURACY units
+END(BorderHashKey)
+
 // describes post-combining effects
 START(filter, filter_desc)
     GENERIC(int, flags)