Support RGBA fonts and bitmap fonts (and RGBA bitmap fonts)

Quite a few things going on in this commit:

- Enable bitmap strikes by default in Paint objects.

The SkPaint parameter that enables bitmap strikes was not previously
included in DEFAULT_PAINT_FLAGS. This effectively disabled bitmap
fonts. Oops! It's for the best, though, as additional work was needed
in Skia to make bitmap fonts work anyway.

- Complain if TEXTURE_BORDER_SIZE is not 1.

Our glyph cache code does not currently handle any value other than 1
here, including zero. I've added a little C preprocessor check to
prevent future engineers (including especially future-me) from
thinking that they can change this value without updating the related
code.

- Add GL_RGBA support to hwui's FontRenderer and friends

This also happened to involve some refactoring for convenience and
cleanliness.

Bug: 9577689
Change-Id: I0abd1e5a0d6623106247fb6421787e2c2f2ea19c

1 files changed, 11 insertions, 2 deletions

diff --git a/libs/hwui/font/CacheTexture.h b/libs/hwui/font/CacheTexture.h
index 208b1ff..028b611 100644
--- a/libs/hwui/font/CacheTexture.h
+++ b/libs/hwui/font/CacheTexture.h
@@ -24,6 +24,7 @@
 #include <utils/Log.h>
 
 #include "FontUtil.h"
+#include "../PixelBuffer.h"
 #include "../Rect.h"
 #include "../Vertex.h"
 
@@ -31,7 +32,6 @@ namespace android {
 namespace uirenderer {
 
 class Caches;
-class PixelBuffer;
 
 /**
  * CacheBlock is a node in a linked list of current free space areas in a CacheTexture.
@@ -74,7 +74,7 @@ struct CacheBlock {
 
 class CacheTexture {
 public:
-    CacheTexture(uint16_t width, uint16_t height, uint32_t maxQuadCount);
+    CacheTexture(uint16_t width, uint16_t height, GLenum format, uint32_t maxQuadCount);
     ~CacheTexture();
 
     void reset();
@@ -100,6 +100,14 @@ public:
         return mHeight;
     }
 
+    inline GLenum getFormat() const {
+        return mFormat;
+    }
+
+    inline uint32_t getOffset(uint16_t x, uint16_t y) const {
+        return (y * mWidth + x) * PixelBuffer::formatSize(mFormat);
+    }
+
     inline const Rect* getDirtyRect() const {
         return &mDirtyRect;
     }
@@ -173,6 +181,7 @@ private:
     GLuint mTextureId;
     uint16_t mWidth;
     uint16_t mHeight;
+    GLenum mFormat;
     bool mLinearFiltering;
     bool mDirty;
     uint16_t mNumGlyphs;