[NOT FOR COMMIT] Fully replace SkCanvas uses.

skia/ext/cdl_surface.h

Index: skia/ext/cdl_surface.h
diff --git a/skia/ext/cdl_surface.h b/skia/ext/cdl_surface.h
new file mode 100644
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+++ b/skia/ext/cdl_surface.h
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+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SKIA_EXT_CDL_SURFACE_H_
+#define SKIA_EXT_CDL_SURFACE_H_
+
+#include "cdl_common.h"
+
+#if CDL_ENABLED
+
+#include "third_party/skia/include/core/SkImage.h"
+#include "third_party/skia/include/core/SkRefCnt.h"
+#include "third_party/skia/include/core/SkSurface.h"
+#include "third_party/skia/include/core/SkSurfaceProps.h"
+
+class GrContext;
+class GrRenderTarget;
+
+class SK_API CdlSurface : public SkRefCnt {
+ public:
+  CdlSurface(sk_sp<SkSurface> surface);
+  ~CdlSurface() override;
+
+  /**
+   *  Create a new surface, using the specified pixels/rowbytes as its
+   *  backend.
+   *
+   *  If the requested surface cannot be created, or the request is not a
+   *  supported configuration, NULL will be returned.
+   *
+   *  Callers are responsible for initialiazing the surface pixels.
+   */
+  static sk_sp<CdlSurface> MakeRasterDirect(const SkImageInfo&,
+                                            void* pixels,
+                                            size_t rowBytes,
+                                            const SkSurfaceProps* = nullptr);
+
+  /**
+   *  The same as NewRasterDirect, but also accepts a call-back routine, which
+   * is invoked
+   *  when the surface is deleted, and is passed the pixel memory and the
+   * specified context.
+   */
+  static sk_sp<CdlSurface> MakeRasterDirectReleaseProc(
+      const SkImageInfo&,
+      void* pixels,
+      size_t rowBytes,
+      void (*releaseProc)(void* pixels, void* context),
+      void* context,
+      const SkSurfaceProps* = nullptr);
+
+  /**
+   *  Return a new surface, with the memory for the pixels automatically
+   * allocated and
+   *  zero-initialized, but respecting the specified rowBytes. If rowBytes==0,
+   * then a default
+   *  value will be chosen. If a non-zero rowBytes is specified, then any images
+   * snapped off of
+   *  this surface (via makeImageSnapshot()) are guaranteed to have the same
+   * rowBytes.
+   *
+   *  If the requested surface cannot be created, or the request is not a
+   *  supported configuration, NULL will be returned.
+   */
+  static sk_sp<CdlSurface> MakeRaster(const SkImageInfo&,
+                                      size_t rowBytes,
+                                      const SkSurfaceProps*);
+
+  /**
+   *  Allocate a new surface, automatically computing the rowBytes.
+   */
+  static sk_sp<CdlSurface> MakeRaster(const SkImageInfo& info,
+                                      const SkSurfaceProps* props = nullptr) {
+    return MakeRaster(info, 0, props);
+  }
+
+  /**
+   *  Helper version of NewRaster. It creates a SkImageInfo with the
+   *  specified width and height, and populates the rest of info to match
+   *  pixels in SkPMColor format.
+   */
+  static sk_sp<CdlSurface> MakeRasterN32Premul(
+      int width,
+      int height,
+      const SkSurfaceProps* props = nullptr) {
+    return MakeRaster(SkImageInfo::MakeN32Premul(width, height), props);
+  }
+
+  /**
+   *  Used to wrap a pre-existing backend 3D API texture as a SkSurface. The
+   * kRenderTarget flag
+   *  must be set on GrBackendTextureDesc for this to succeed. Skia will not
+   * assume ownership
+   *  of the texture and the client must ensure the texture is valid for the
+   * lifetime of the
+   *  SkSurface.
+   */
+  static sk_sp<CdlSurface> MakeFromBackendTexture(GrContext*,
+                                                  const GrBackendTextureDesc&,
+                                                  sk_sp<SkColorSpace>,
+                                                  const SkSurfaceProps*);
+
+  /**
+   *  Used to wrap a pre-existing 3D API rendering target as a SkSurface. Skia
+   * will not assume
+   *  ownership of the render target and the client must ensure the render
+   * target is valid for the
+   *  lifetime of the SkSurface.
+   */
+  static sk_sp<CdlSurface> MakeFromBackendRenderTarget(
+      GrContext*,
+      const GrBackendRenderTargetDesc&,
+      sk_sp<SkColorSpace>,
+      const SkSurfaceProps*);
+
+  /**
+   *  Used to wrap a pre-existing 3D API texture as a SkSurface. Skia will treat
+   * the texture as
+   *  a rendering target only, but unlike NewFromBackendRenderTarget, Skia will
+   * manage and own
+   *  the associated render target objects (but not the provided texture). The
+   * kRenderTarget flag
+   *  must be set on GrBackendTextureDesc for this to succeed. Skia will not
+   * assume ownership
+   *  of the texture and the client must ensure the texture is valid for the
+   * lifetime of the
+   *  SkSurface.
+   */
+  static sk_sp<CdlSurface> MakeFromBackendTextureAsRenderTarget(
+      GrContext*,
+      const GrBackendTextureDesc&,
+      sk_sp<SkColorSpace>,
+      const SkSurfaceProps*);
+
+  /**
+   * Legacy versions of the above factories, without color space support. These
+   * create "legacy"
+   * surfaces that operate without gamma correction or color management.
+   */
+  static sk_sp<CdlSurface> MakeFromBackendTexture(
+      GrContext* ctx,
+      const GrBackendTextureDesc& desc,
+      const SkSurfaceProps* props) {
+    return MakeFromBackendTexture(ctx, desc, nullptr, props);
+  }
+
+  static sk_sp<CdlSurface> MakeFromBackendRenderTarget(
+      GrContext* ctx,
+      const GrBackendRenderTargetDesc& desc,
+      const SkSurfaceProps* props) {
+    return MakeFromBackendRenderTarget(ctx, desc, nullptr, props);
+  }
+
+  static sk_sp<CdlSurface> MakeFromBackendTextureAsRenderTarget(
+      GrContext* ctx,
+      const GrBackendTextureDesc& desc,
+      const SkSurfaceProps* props) {
+    return MakeFromBackendTextureAsRenderTarget(ctx, desc, nullptr, props);
+  }
+
+  /**
+   *  Return a new surface whose contents will be drawn to an offscreen
+   *  render target, allocated by the surface.
+   */
+  static sk_sp<CdlSurface> MakeRenderTarget(GrContext*,
+                                            SkBudgeted,
+                                            const SkImageInfo&,
+                                            int sampleCount,
+                                            GrSurfaceOrigin,
+                                            const SkSurfaceProps*);
+
+  static sk_sp<CdlSurface> MakeRenderTarget(GrContext* context,
+                                            SkBudgeted budgeted,
+                                            const SkImageInfo& info,
+                                            int sampleCount,
+                                            const SkSurfaceProps* props) {
+    return MakeRenderTarget(context, budgeted, info, sampleCount,
+                            kBottomLeft_GrSurfaceOrigin, props);
+  }
+
+  static sk_sp<CdlSurface> MakeRenderTarget(GrContext* gr,
+                                            SkBudgeted b,
+                                            const SkImageInfo& info) {
+    if (!info.width() || !info.height()) {
+      return nullptr;
+    }
+    return MakeRenderTarget(gr, b, info, 0, kBottomLeft_GrSurfaceOrigin,
+                            nullptr);
+  }
+
+  int width() const { return surface_->width(); }
+  int height() const { return surface_->height(); }
+
+  /**
+   *  Returns a unique non-zero, unique value identifying the content of this
+   *  surface. Each time the content is changed changed, either by drawing
+   *  into this surface, or explicitly calling notifyContentChanged()) this
+   *  method will return a new value.
+   *
+   *  If this surface is empty (i.e. has a zero-dimention), this will return
+   *  0.
+   */
+  uint32_t generationID() { return surface_->generationID(); }
+
+  /**
+   *  Call this if the contents are about to change. This will (lazily) force a
+   * new
+   *  value to be returned from generationID() when it is called next.
+   *
+   *  CAN WE DEPRECATE THIS?
+   */
+  void notifyContentWillChange(SkSurface::ContentChangeMode mode) {
+    surface_->notifyContentWillChange(mode);
+  }
+
+  enum BackendHandleAccess {
+    kFlushRead_BackendHandleAccess,     //!< caller may read from the backend
+                                        //! object
+    kFlushWrite_BackendHandleAccess,    //!< caller may write to the backend
+                                        //! object
+    kDiscardWrite_BackendHandleAccess,  //!< caller must over-write the entire
+                                        //! backend object
+  };
+
+  /*
+   * These are legacy aliases which will be removed soon
+   */
+  static const BackendHandleAccess kFlushRead_TextureHandleAccess =
+      kFlushRead_BackendHandleAccess;
+  static const BackendHandleAccess kFlushWrite_TextureHandleAccess =
+      kFlushWrite_BackendHandleAccess;
+  static const BackendHandleAccess kDiscardWrite_TextureHandleAccess =
+      kDiscardWrite_BackendHandleAccess;
+
+  /**
+   *  Retrieves the backend API handle of the texture used by this surface, or 0
+   * if the surface
+   *  is not backed by a GPU texture.
+   *
+   *  The returned texture-handle is only valid until the next draw-call into
+   * the surface,
+   *  or the surface is deleted.
+   */
+  GrBackendObject getTextureHandle(BackendHandleAccess);
+
+  /**
+   *  Retrieves the backend API handle of the RenderTarget backing this surface.
+   * Callers must
+   *  ensure this function returns 'true' or else the GrBackendObject will be
+   * invalid
+   *
+   *  In OpenGL this will return the FramebufferObject ID.
+   */
+  bool getRenderTargetHandle(GrBackendObject*, BackendHandleAccess);
+
+  /**
+   *  Return a canvas that will draw into this surface. This will always
+   *  return the same canvas for a given surface, and is manged/owned by the
+   *  surface. It should not be used when its parent surface has gone out of
+   *  scope.
+   */
+  CdlCanvas* getCanvas();
+
+  /**
+   *  Return a new surface that is "compatible" with this one, in that it will
+   *  efficiently be able to be drawn into this surface. Typical calling
+   *  pattern:
+   *
+   *  SkSurface* A = SkSurface::New...();
+   *  SkCanvas* canvasA = surfaceA->newCanvas();
+   *  ...
+   *  SkSurface* surfaceB = surfaceA->newSurface(...);
+   *  SkCanvas* canvasB = surfaceB->newCanvas();
+   *  ... // draw using canvasB
+   *  canvasA->drawSurface(surfaceB); // <--- this will always be optimal!
+   */
+  sk_sp<SkSurface> makeSurface(const SkImageInfo&);
+
+  /**
+   *  Returns an image of the current state of the surface pixels up to this
+   *  point. Subsequent changes to the surface (by drawing into its canvas)
+   *  will not be reflected in this image. If a copy must be made the Budgeted
+   *  parameter controls whether it counts against the resource budget
+   *  (currently for the gpu backend only).
+   */
+  sk_sp<SkImage> makeImageSnapshot(SkBudgeted = SkBudgeted::kYes);
+
+  /**
+   * In rare instances a client may want a unique copy of the SkSurface's
+   * contents in an image
+   * snapshot. This enum can be used to enforce that the image snapshot's
+   * backing store is not
+   * shared with another image snapshot or the surface's backing store. This is
+   * generally more
+   * expensive. This was added for Chromium bug 585250.
+   */
+  enum ForceUnique { kNo_ForceUnique, kYes_ForceUnique };
+  sk_sp<SkImage> makeImageSnapshot(SkBudgeted, ForceUnique);
+
+  /**
+   *  Though the caller could get a snapshot image explicitly, and draw that,
+   *  it seems that directly drawing a surface into another canvas might be
+   *  a common pattern, and that we could possibly be more efficient, since
+   *  we'd know that the "snapshot" need only live until we've handed it off
+   *  to the canvas.
+   */
+  void draw(CdlCanvas*, SkScalar x, SkScalar y, const CdlPaint*);
+
+  /**
+   *  If the surface has direct access to its pixels (i.e. they are in local
+   *  RAM) return true, and if not null, set the pixmap parameter to point to
+   * the information
+   *  about the surface's pixels. The pixel address in the pixmap is only valid
+   * while
+   *  the surface object is in scope, and no API call is made on the surface
+   *  or its canvas.
+   *
+   *  On failure, returns false and the pixmap parameter is ignored.
+   */
+  bool peekPixels(SkPixmap*);
+
+  /**
+   *  Copy the pixels from the surface into the specified buffer (pixels +
+   * rowBytes),
+   *  converting them into the requested format (dstInfo). The surface pixels
+   * are read
+   *  starting at the specified (srcX,srcY) location.
+   *
+   *  The specified ImageInfo and (srcX,srcY) offset specifies a source
+   * rectangle
+   *
+   *      srcR.setXYWH(srcX, srcY, dstInfo.width(), dstInfo.height());
+   *
+   *  srcR is intersected with the bounds of the base-layer. If this
+   * intersection is not empty,
+   *  then we have two sets of pixels (of equal size). Replace the dst pixels
+   * with the
+   *  corresponding src pixels, performing any colortype/alphatype
+   * transformations needed
+   *  (in the case where the src and dst have different colortypes or
+   * alphatypes).
+   *
+   *  This call can fail, returning false, for several reasons:
+   *  - If srcR does not intersect the surface bounds.
+   *  - If the requested colortype/alphatype cannot be converted from the
+   * surface's types.
+   */
+  bool readPixels(const SkImageInfo& dstInfo,
+                  void* dstPixels,
+                  size_t dstRowBytes,
+                  int srcX,
+                  int srcY);
+
+  const SkSurfaceProps& props() const { return surface_->props(); }
+
+  /**
+   * Issue any pending surface IO to the current backend 3D API and resolve any
+   * surface MSAA.
+   */
+  void prepareForExternalIO();
+
+ private:
+  sk_sp<SkSurface> surface_;
+  std::unique_ptr<CdlCanvas> canvas_;
+};
+
+#endif  // CDL_ENABLED
+
+#endif  // SKIA_EXT_CDL_SURFACE_H_