Add Atlas Text interface for rendering SDF glyphs.

This new API is built upon SDF text atlas code from the GPU backend. Unlike using the GPU
backend to draw text, this set of interfaces allows the client to render the SDF glyphs. The
client issues text draws to potentially multiple targets and then the client flushes. The
client then gets commands from Skia with data to put into a texture atlas and vertices to
draw that reference the texture. The client is responsible for creating the texture, uploading
the SDF data to the texture, and drawing the vertices provided by Skia.

Change-Id: Ie9447e19b85f0ce1c2b942e5216c787a74f335d3
Reviewed-on: https://skia-review.googlesource.com/59360
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>

1 files changed, 16 insertions, 10 deletions

diff --git a/src/gpu/ops/GrAtlasTextOp.h b/src/gpu/ops/GrAtlasTextOp.h
index 240b98b6f0..c8ef643fd2 100644
--- a/src/gpu/ops/GrAtlasTextOp.h
+++ b/src/gpu/ops/GrAtlasTextOp.h
@@ -12,6 +12,8 @@
 #include "text/GrAtlasTextContext.h"
 #include "text/GrDistanceFieldAdjustTable.h"
 
+class SkAtlasTextTarget;
+
 class GrAtlasTextOp final : public GrMeshDrawOp {
 public:
     DEFINE_OP_CLASS_ID
@@ -116,6 +118,20 @@ public:
     RequiresDstTexture finalize(const GrCaps& caps, const GrAppliedClip* clip,
                                 GrPixelConfigIsClamped dstIsClamped) override;
 
+    enum MaskType {
+        kGrayscaleCoverageMask_MaskType,
+        kLCDCoverageMask_MaskType,
+        kColorBitmapMask_MaskType,
+        kAliasedDistanceField_MaskType,
+        kGrayscaleDistanceField_MaskType,
+        kLCDDistanceField_MaskType,
+        kLCDBGRDistanceField_MaskType,
+    };
+
+    MaskType maskType() const { return fMaskType; }
+
+    void executeForTextTarget(SkAtlasTextTarget*, uint32_t color);
+
 private:
     // The minimum number of Geometry we will try to allocate.
     static constexpr auto kMinGeometryAllocated = 12;
@@ -180,16 +196,6 @@ private:
 
     sk_sp<GrGeometryProcessor> setupDfProcessor() const;
 
-    enum MaskType {
-        kGrayscaleCoverageMask_MaskType,
-        kLCDCoverageMask_MaskType,
-        kColorBitmapMask_MaskType,
-        kAliasedDistanceField_MaskType,
-        kGrayscaleDistanceField_MaskType,
-        kLCDDistanceField_MaskType,
-        kLCDBGRDistanceField_MaskType,
-    };
-
     SkAutoSTMalloc<kMinGeometryAllocated, Geometry> fGeoData;
     int fGeoDataAllocSize;
     GrColor fColor;