Split drawing functionality out of GrContext and into new GrDrawContext

include/gpu/GrDrawContext.h

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrDawContext_DEFINED
+#define GrDrawContext_DEFINED
+
+#include "SkRefCnt.h"
+#include "GrDrawTarget.h"  // TODO: remove this
+
+/*
+ * A helper object to orchestrate draws
+ */
+class SK_API GrDrawContext : public SkRefCnt {
+public:
+    SK_DECLARE_INST_COUNT(GrDrawContext)
+
+    void copySurface(GrRenderTarget* dst, GrSurface* src,
+                     const SkIRect& srcRect, const SkIPoint& dstPoint);
+
+    // drawText and drawPaths are thanks to the GrAtlasTextContext and the 
+    // GrStencilAndCoverTextContext respectively
+    // TODO: remove these two
+    void drawText(GrPipelineBuilder* pipelineBuilder, GrBatch* batch);
+
+    void drawPaths(GrPipelineBuilder* pipelineBuilder,
+                   const GrPathProcessor* pathProc,
+                   const GrPathRange* pathRange,
+                   const void* indices,
+                   GrDrawTarget::PathIndexType indexType,
+                   const float transformValues[],
+                   GrDrawTarget::PathTransformType transformType,
+                   int count,
+                   GrPathRendering::FillType fill);
+
+    /**
+     * Provides a perfomance hint that the render target's contents are allowed
+     * to become undefined.
+     */
+    void discard(GrRenderTarget*);
+
+    /**
+     * Clear the entire or rect of the render target, ignoring any clips.
+     * @param target The render target to clear.
+     * @param rect  the rect to clear or the whole thing if rect is NULL.
+     * @param color the color to clear to.
+     * @param canIgnoreRect allows partial clears to be converted to whole
+     *                      clears on platforms for which that is cheap
+     */
+    void clear(GrRenderTarget*, const SkIRect* rect, GrColor color, bool canIgnoreRect);
+
+    /**
+     *  Draw everywhere (respecting the clip) with the paint.
+     */
+    void drawPaint(GrRenderTarget*, const GrClip&, const GrPaint&, const SkMatrix& viewMatrix);
+
+    /**
+     *  Draw the rect using a paint.
+     *  @param paint        describes how to color pixels.
+     *  @param viewMatrix   transformation matrix
+     *  @param strokeInfo   the stroke information (width, join, cap), and.
+     *                      the dash information (intervals, count, phase).
+     *                      If strokeInfo == NULL, then the rect is filled.
+     *                      Otherwise, if stroke width == 0, then the stroke
+     *                      is always a single pixel thick, else the rect is
+     *                      mitered/beveled stroked based on stroke width.
+     *  The rects coords are used to access the paint (through texture matrix)
+     */
+    void drawRect(GrRenderTarget*,
+                  const GrClip&,
+                  const GrPaint& paint,
+                  const SkMatrix& viewMatrix,
+                  const SkRect&,
+                  const GrStrokeInfo* strokeInfo = NULL);
+
+    /**
+     * Maps a rectangle of shader coordinates to a rectangle and draws that rectangle
+     *
+     * @param paint         describes how to color pixels.
+     * @param viewMatrix    transformation matrix which applies to rectToDraw
+     * @param rectToDraw    the rectangle to draw
+     * @param localRect     the rectangle of shader coordinates applied to rectToDraw
+     * @param localMatrix   an optional matrix to transform the shader coordinates before applying
+     *                      to rectToDraw
+     */
+    void drawNonAARectToRect(GrRenderTarget*,
+                             const GrClip&,
+                             const GrPaint& paint,
+                             const SkMatrix& viewMatrix,
+                             const SkRect& rectToDraw,
+                             const SkRect& localRect,
+                             const SkMatrix* localMatrix = NULL);
+
+    /**
+     * Draws a non-AA rect with paint and a localMatrix
+     */
+    void drawNonAARectWithLocalMatrix(GrRenderTarget* rt,
+                                      const GrClip& clip,
+                                      const GrPaint& paint,
+                                      const SkMatrix& viewMatrix,
+                                      const SkRect& rect,
+                                      const SkMatrix& localMatrix) {
+        this->drawNonAARectToRect(rt, clip, paint, viewMatrix, rect, rect, &localMatrix);
+    }
+
+    /**
+     *  Draw a roundrect using a paint.
+     *
+     *  @param paint        describes how to color pixels.
+     *  @param viewMatrix   transformation matrix
+     *  @param rrect        the roundrect to draw
+     *  @param strokeInfo   the stroke information (width, join, cap) and
+     *                      the dash information (intervals, count, phase).
+     */
+    void drawRRect(GrRenderTarget*,
+                   const GrClip&,
+                   const GrPaint&,
+                   const SkMatrix& viewMatrix,
+                   const SkRRect& rrect,
+                   const GrStrokeInfo&);
+
+    /**
+     *  Shortcut for drawing an SkPath consisting of nested rrects using a paint.
+     *  Does not support stroking. The result is undefined if outer does not contain
+     *  inner.
+     *
+     *  @param paint        describes how to color pixels.
+     *  @param viewMatrix   transformation matrix
+     *  @param outer        the outer roundrect
+     *  @param inner        the inner roundrect
+     */
+    void drawDRRect(GrRenderTarget*,
+                    const GrClip&,
+                    const GrPaint&,
+                    const SkMatrix& viewMatrix,
+                    const SkRRect& outer,
+                    const SkRRect& inner);
+
+
+    /**
+     * Draws a path.
+     *
+     * @param paint         describes how to color pixels.
+     * @param viewMatrix    transformation matrix
+     * @param path          the path to draw
+     * @param strokeInfo    the stroke information (width, join, cap) and
+     *                      the dash information (intervals, count, phase).
+     */
+    void drawPath(GrRenderTarget*,
+                  const GrClip&,
+                  const GrPaint&,
+                  const SkMatrix& viewMatrix,
+                  const SkPath&,
+                  const GrStrokeInfo&);
+
+    /**
+     * Draws vertices with a paint.
+     *
+     * @param   paint           describes how to color pixels.
+     * @param   viewMatrix      transformation matrix
+     * @param   primitiveType   primitives type to draw.
+     * @param   vertexCount     number of vertices.
+     * @param   positions       array of vertex positions, required.
+     * @param   texCoords       optional array of texture coordinates used
+     *                          to access the paint.
+     * @param   colors          optional array of per-vertex colors, supercedes
+     *                          the paint's color field.
+     * @param   indices         optional array of indices. If NULL vertices
+     *                          are drawn non-indexed.
+     * @param   indexCount      if indices is non-null then this is the
+     *                          number of indices.
+     */
+    void drawVertices(GrRenderTarget*,
+                      const GrClip&,
+                      const GrPaint& paint,
+                      const SkMatrix& viewMatrix,
+                      GrPrimitiveType primitiveType,
+                      int vertexCount,
+                      const SkPoint positions[],
+                      const SkPoint texs[],
+                      const GrColor colors[],
+                      const uint16_t indices[],
+                      int indexCount);
+
+    /**
+     * Draws an oval.
+     *
+     * @param paint         describes how to color pixels.
+     * @param viewMatrix    transformation matrix
+     * @param oval          the bounding rect of the oval.
+     * @param strokeInfo    the stroke information (width, join, cap) and
+     *                      the dash information (intervals, count, phase).
+     */
+    void drawOval(GrRenderTarget*,
+                  const GrClip&,
+                  const GrPaint& paint,
+                  const SkMatrix& viewMatrix,
+                  const SkRect& oval,
+                  const GrStrokeInfo& strokeInfo);
+
+
+private:
+    friend class GrContext; // for ctor
+
+    GrDrawContext(GrContext* context, GrDrawTarget* drawTarget);
+
+    // Sets the paint. Returns true on success; false on failure.
+    bool prepareToDraw(GrPipelineBuilder*,
+                       GrRenderTarget* rt,
+                       const GrClip&,
+                       const GrPaint* paint);
+
+    // A simpler version of the above which just returns true on success; false on failure.  
+    // Clip is *NOT* set
+    bool prepareToDraw(GrRenderTarget* rt);
+
+    void internalDrawPath(GrDrawTarget*,
+                          GrPipelineBuilder*,
+                          const SkMatrix& viewMatrix,
+                          GrColor,
+                          bool useAA,
+                          const SkPath&,
+                          const GrStrokeInfo&);
+
+    GrContext*                     fContext;     // owning context -> no ref
+    SkAutoTUnref<GrDrawTarget>     fDrawTarget;
+};
+
+#endif