1 files changed, 71 insertions, 0 deletions
diff --git a/include/atlastext/SkAtlasTextRenderer.h b/include/atlastext/SkAtlasTextRenderer.h
new file mode 100644
index 0000000000..a78e270edb
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+++ b/include/atlastext/SkAtlasTextRenderer.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkPoint.h"
+#include "SkRefCnt.h"
+
+#ifndef SkAtlasTextRenderer_DEFINED
+#define SkAtlasTextRenderer_DEFINED
+
+/**
+ * This is the base class for a renderer implemented by the SkAtlasText client. The
+ * SkAtlasTextContext issues texture creations, deletions, uploads, and vertex draws to the
+ * renderer. The renderer must perform those actions in the order called to correctly render
+ * the text drawn to SkAtlasTextTargets.
+ */
+class SK_API SkAtlasTextRenderer : public SkRefCnt {
+public:
+    enum class AtlasFormat {
+        /** Unsigned normalized 8 bit single channel format. */
+        kA8
+    };
+
+    struct SDFVertex {
+        /** Position in device space (not normalized). */
+        SkPoint fPosition;
+        /** Color, same value for all four corners of a glyph quad. */
+        uint32_t fColor;
+        /** Texture coordinate (in texel units, not normalized). */
+        SkIPoint16 fTextureCoord;
+    };
+
+    virtual ~SkAtlasTextRenderer() = default;
+
+    /**
+     * Create a texture of the provided format with dimensions 'width' x 'height'
+     * and return a unique handle.
+     */
+    virtual void* createTexture(AtlasFormat, int width, int height) = 0;
+
+    /**
+     * Delete the texture with the passed handle.
+     */
+    virtual void deleteTexture(void* textureHandle) = 0;
+
+    /**
+     * Place the pixel data specified by 'data' in the texture with handle
+     * 'textureHandle' in the rectangle ['x', 'x' + 'width') x ['y', 'y' + 'height').
+     * 'rowBytes' specifies the byte offset between successive rows in 'data' and will always be
+     * a multiple of the number of bytes per pixel.
+     * The pixel format of data is the same as that of 'textureHandle'.
+     */
+    virtual void setTextureData(void* textureHandle, const void* data, int x, int y, int width,
+                                int height, size_t rowBytes) = 0;
+
+    /**
+     * Draws glyphs using SDFs. The SDF data resides in 'textureHandle'. The array
+     * 'vertices' provides interleaved device-space positions, colors, and
+     * texture coordinates. There are are 4 * 'quadCnt' entries in 'vertices'.
+     */
+    virtual void drawSDFGlyphs(void* targetHandle, void* textureHandle, const SDFVertex vertices[],
+                               int quadCnt) = 0;
+
+    /** Called when a SkAtlasTextureTarget is destroyed. */
+    virtual void targetDeleted(void* targetHandle) = 0;
+};
+
+#endif