michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkCanvasStateUtils.h"
michael@0: 
michael@0: #include "SkBitmapDevice.h"
michael@0: #include "SkCanvas.h"
michael@0: #include "SkCanvasStack.h"
michael@0: #include "SkErrorInternals.h"
michael@0: #include "SkWriter32.h"
michael@0: 
michael@0: #define CANVAS_STATE_VERSION 1
michael@0: /*
michael@0:  * WARNING: The structs below are part of a stable ABI and as such we explicitly
michael@0:  * use unambigious primitives (e.g. int32_t instead of an enum).
michael@0:  *
michael@0:  * ANY CHANGES TO THE STRUCTS BELOW THAT IMPACT THE ABI SHOULD RESULT IN AN
michael@0:  * UPDATE OF THE CANVAS_STATE_VERSION. SUCH CHANGES SHOULD ONLY BE MADE IF
michael@0:  * ABSOLUTELY NECESSARY!
michael@0:  */
michael@0: enum RasterConfigs {
michael@0:   kUnknown_RasterConfig   = 0,
michael@0:   kRGB_565_RasterConfig   = 1,
michael@0:   kARGB_8888_RasterConfig = 2
michael@0: };
michael@0: typedef int32_t RasterConfig;
michael@0: 
michael@0: enum CanvasBackends {
michael@0:     kUnknown_CanvasBackend = 0,
michael@0:     kRaster_CanvasBackend  = 1,
michael@0:     kGPU_CanvasBackend     = 2,
michael@0:     kPDF_CanvasBackend     = 3
michael@0: };
michael@0: typedef int32_t CanvasBackend;
michael@0: 
michael@0: struct ClipRect {
michael@0:     int32_t left, top, right, bottom;
michael@0: };
michael@0: 
michael@0: struct SkMCState {
michael@0:     float matrix[9];
michael@0:     // NOTE: this only works for non-antialiased clips
michael@0:     int32_t clipRectCount;
michael@0:     ClipRect* clipRects;
michael@0: };
michael@0: 
michael@0: // NOTE: If you add more members, bump CanvasState::version.
michael@0: struct SkCanvasLayerState {
michael@0:     CanvasBackend type;
michael@0:     int32_t x, y;
michael@0:     int32_t width;
michael@0:     int32_t height;
michael@0: 
michael@0:     SkMCState mcState;
michael@0: 
michael@0:     union {
michael@0:         struct {
michael@0:             RasterConfig config; // pixel format: a value from RasterConfigs.
michael@0:             size_t rowBytes;     // Number of bytes from start of one line to next.
michael@0:             void* pixels;        // The pixels, all (height * rowBytes) of them.
michael@0:         } raster;
michael@0:         struct {
michael@0:             int32_t textureID;
michael@0:         } gpu;
michael@0:     };
michael@0: };
michael@0: 
michael@0: class SkCanvasState {
michael@0: public:
michael@0:     SkCanvasState(SkCanvas* canvas) {
michael@0:         SkASSERT(canvas);
michael@0:         version = CANVAS_STATE_VERSION;
michael@0:         width = canvas->getDeviceSize().width();
michael@0:         height = canvas->getDeviceSize().height();
michael@0:         layerCount = 0;
michael@0:         layers = NULL;
michael@0:         originalCanvas = SkRef(canvas);
michael@0: 
michael@0:         mcState.clipRectCount = 0;
michael@0:         mcState.clipRects = NULL;
michael@0:     }
michael@0: 
michael@0:     ~SkCanvasState() {
michael@0:         // loop through the layers and free the data allocated to the clipRects
michael@0:         for (int i = 0; i < layerCount; ++i) {
michael@0:             sk_free(layers[i].mcState.clipRects);
michael@0:         }
michael@0: 
michael@0:         sk_free(mcState.clipRects);
michael@0:         sk_free(layers);
michael@0: 
michael@0:         // it is now safe to free the canvas since there should be no remaining
michael@0:         // references to the content that is referenced by this canvas (e.g. pixels)
michael@0:         originalCanvas->unref();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * The version this struct was built with.  This field must always appear
michael@0:      * first in the struct so that when the versions don't match (and the
michael@0:      * remaining contents and size are potentially different) we can still
michael@0:      * compare the version numbers.
michael@0:      */
michael@0:     int32_t version;
michael@0: 
michael@0:     int32_t width;
michael@0:     int32_t height;
michael@0: 
michael@0:     SkMCState mcState;
michael@0: 
michael@0:     int32_t layerCount;
michael@0:     SkCanvasLayerState* layers;
michael@0: 
michael@0: private:
michael@0:     SkCanvas* originalCanvas;
michael@0: };
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class ClipValidator : public SkCanvas::ClipVisitor {
michael@0: public:
michael@0:     ClipValidator() : fFailed(false) {}
michael@0:     bool failed() { return fFailed; }
michael@0: 
michael@0:     // ClipVisitor
michael@0:     virtual void clipRect(const SkRect& rect, SkRegion::Op op, bool antialias) SK_OVERRIDE {
michael@0:         fFailed |= antialias;
michael@0:     }
michael@0: 
michael@0:     virtual void clipRRect(const SkRRect& rrect, SkRegion::Op op, bool antialias) SK_OVERRIDE {
michael@0:         fFailed |= antialias;
michael@0:     }
michael@0: 
michael@0:     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) SK_OVERRIDE {
michael@0:         fFailed |= antialias;
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     bool fFailed;
michael@0: };
michael@0: 
michael@0: static void setup_MC_state(SkMCState* state, const SkMatrix& matrix, const SkRegion& clip) {
michael@0:     // initialize the struct
michael@0:     state->clipRectCount = 0;
michael@0: 
michael@0:     // capture the matrix
michael@0:     for (int i = 0; i < 9; i++) {
michael@0:         state->matrix[i] = matrix.get(i);
michael@0:     }
michael@0: 
michael@0:     /*
michael@0:      * capture the clip
michael@0:      *
michael@0:      * storage is allocated on the stack for the first 4 rects. This value was
michael@0:      * chosen somewhat arbitrarily, but does allow us to represent simple clips
michael@0:      * and some more common complex clips (e.g. a clipRect with a sub-rect
michael@0:      * clipped out of its interior) without needing to malloc any additional memory.
michael@0:      */
michael@0:     SkSWriter32<4*sizeof(ClipRect)> clipWriter;
michael@0: 
michael@0:     if (!clip.isEmpty()) {
michael@0:         // only returns the b/w clip so aa clips fail
michael@0:         SkRegion::Iterator clip_iterator(clip);
michael@0:         for (; !clip_iterator.done(); clip_iterator.next()) {
michael@0:             // this assumes the SkIRect is stored in l,t,r,b ordering which
michael@0:             // matches the ordering of our ClipRect struct
michael@0:             clipWriter.writeIRect(clip_iterator.rect());
michael@0:             state->clipRectCount++;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // allocate memory for the clip then and copy them to the struct
michael@0:     state->clipRects = (ClipRect*) sk_malloc_throw(clipWriter.bytesWritten());
michael@0:     clipWriter.flatten(state->clipRects);
michael@0: }
michael@0: 
michael@0: 
michael@0: 
michael@0: SkCanvasState* SkCanvasStateUtils::CaptureCanvasState(SkCanvas* canvas) {
michael@0:     SkASSERT(canvas);
michael@0: 
michael@0:     // Check the clip can be decomposed into rectangles (i.e. no soft clips).
michael@0:     ClipValidator validator;
michael@0:     canvas->replayClips(&validator);
michael@0:     if (validator.failed()) {
michael@0:         SkErrorInternals::SetError(kInvalidOperation_SkError,
michael@0:                 "CaptureCanvasState does not support canvases with antialiased clips.\n");
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     SkAutoTDelete<SkCanvasState> canvasState(SkNEW_ARGS(SkCanvasState, (canvas)));
michael@0: 
michael@0:     // decompose the total matrix and clip
michael@0:     setup_MC_state(&canvasState->mcState, canvas->getTotalMatrix(),
michael@0:                    canvas->internal_private_getTotalClip());
michael@0: 
michael@0:     /*
michael@0:      * decompose the layers
michael@0:      *
michael@0:      * storage is allocated on the stack for the first 3 layers. It is common in
michael@0:      * some view systems (e.g. Android) that a few non-clipped layers are present
michael@0:      * and we will not need to malloc any additional memory in those cases.
michael@0:      */
michael@0:     SkSWriter32<3*sizeof(SkCanvasLayerState)> layerWriter;
michael@0:     int layerCount = 0;
michael@0:     for (SkCanvas::LayerIter layer(canvas, true/*skipEmptyClips*/); !layer.done(); layer.next()) {
michael@0: 
michael@0:         // we currently only work for bitmap backed devices
michael@0:         const SkBitmap& bitmap = layer.device()->accessBitmap(true/*changePixels*/);
michael@0:         if (bitmap.empty() || bitmap.isNull() || !bitmap.lockPixelsAreWritable()) {
michael@0:             return NULL;
michael@0:         }
michael@0: 
michael@0:         SkCanvasLayerState* layerState =
michael@0:                 (SkCanvasLayerState*) layerWriter.reserve(sizeof(SkCanvasLayerState));
michael@0:         layerState->type = kRaster_CanvasBackend;
michael@0:         layerState->x = layer.x();
michael@0:         layerState->y = layer.y();
michael@0:         layerState->width = bitmap.width();
michael@0:         layerState->height = bitmap.height();
michael@0: 
michael@0:         switch (bitmap.colorType()) {
michael@0:             case kPMColor_SkColorType:
michael@0:                 layerState->raster.config = kARGB_8888_RasterConfig;
michael@0:                 break;
michael@0:             case kRGB_565_SkColorType:
michael@0:                 layerState->raster.config = kRGB_565_RasterConfig;
michael@0:                 break;
michael@0:             default:
michael@0:                 return NULL;
michael@0:         }
michael@0:         layerState->raster.rowBytes = bitmap.rowBytes();
michael@0:         layerState->raster.pixels = bitmap.getPixels();
michael@0: 
michael@0:         setup_MC_state(&layerState->mcState, layer.matrix(), layer.clip());
michael@0:         layerCount++;
michael@0:     }
michael@0: 
michael@0:     // allocate memory for the layers and then and copy them to the struct
michael@0:     SkASSERT(layerWriter.bytesWritten() == layerCount * sizeof(SkCanvasLayerState));
michael@0:     canvasState->layerCount = layerCount;
michael@0:     canvasState->layers = (SkCanvasLayerState*) sk_malloc_throw(layerWriter.bytesWritten());
michael@0:     layerWriter.flatten(canvasState->layers);
michael@0: 
michael@0:     // for now, just ignore any client supplied DrawFilter.
michael@0:     if (canvas->getDrawFilter()) {
michael@0: //        SkDEBUGF(("CaptureCanvasState will ignore the canvases draw filter.\n"));
michael@0:     }
michael@0: 
michael@0:     return canvasState.detach();
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: static void setup_canvas_from_MC_state(const SkMCState& state, SkCanvas* canvas) {
michael@0:     // reconstruct the matrix
michael@0:     SkMatrix matrix;
michael@0:     for (int i = 0; i < 9; i++) {
michael@0:         matrix.set(i, state.matrix[i]);
michael@0:     }
michael@0: 
michael@0:     // reconstruct the clip
michael@0:     SkRegion clip;
michael@0:     for (int i = 0; i < state.clipRectCount; ++i) {
michael@0:         clip.op(SkIRect::MakeLTRB(state.clipRects[i].left,
michael@0:                                   state.clipRects[i].top,
michael@0:                                   state.clipRects[i].right,
michael@0:                                   state.clipRects[i].bottom),
michael@0:                 SkRegion::kUnion_Op);
michael@0:     }
michael@0: 
michael@0:     canvas->setMatrix(matrix);
michael@0:     canvas->setClipRegion(clip);
michael@0: }
michael@0: 
michael@0: static SkCanvas* create_canvas_from_canvas_layer(const SkCanvasLayerState& layerState) {
michael@0:     SkASSERT(kRaster_CanvasBackend == layerState.type);
michael@0: 
michael@0:     SkBitmap bitmap;
michael@0:     SkColorType colorType =
michael@0:         layerState.raster.config == kARGB_8888_RasterConfig ? kPMColor_SkColorType :
michael@0:         layerState.raster.config == kRGB_565_RasterConfig ? kRGB_565_SkColorType :
michael@0:         kUnknown_SkColorType;
michael@0: 
michael@0:     if (colorType == kUnknown_SkColorType) {
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     bitmap.installPixels(SkImageInfo::Make(layerState.width, layerState.height,
michael@0:                                            colorType, kPremul_SkAlphaType),
michael@0:                          layerState.raster.pixels, layerState.raster.rowBytes,
michael@0:                          NULL, NULL);
michael@0: 
michael@0:     SkASSERT(!bitmap.empty());
michael@0:     SkASSERT(!bitmap.isNull());
michael@0: 
michael@0:     SkAutoTUnref<SkCanvas> canvas(SkNEW_ARGS(SkCanvas, (bitmap)));
michael@0: 
michael@0:     // setup the matrix and clip
michael@0:     setup_canvas_from_MC_state(layerState.mcState, canvas.get());
michael@0: 
michael@0:     return canvas.detach();
michael@0: }
michael@0: 
michael@0: SkCanvas* SkCanvasStateUtils::CreateFromCanvasState(const SkCanvasState* state) {
michael@0:     SkASSERT(state);
michael@0: 
michael@0:     // check that the versions match
michael@0:     if (CANVAS_STATE_VERSION != state->version) {
michael@0:         SkDebugf("CreateFromCanvasState version does not match the one use to create the input");
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     if (state->layerCount < 1) {
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     SkAutoTUnref<SkCanvasStack> canvas(SkNEW_ARGS(SkCanvasStack, (state->width, state->height)));
michael@0: 
michael@0:     // setup the matrix and clip on the n-way canvas
michael@0:     setup_canvas_from_MC_state(state->mcState, canvas);
michael@0: 
michael@0:     // Iterate over the layers and add them to the n-way canvas
michael@0:     for (int i = state->layerCount - 1; i >= 0; --i) {
michael@0:         SkAutoTUnref<SkCanvas> canvasLayer(create_canvas_from_canvas_layer(state->layers[i]));
michael@0:         if (!canvasLayer.get()) {
michael@0:             return NULL;
michael@0:         }
michael@0:         canvas->pushCanvas(canvasLayer.get(), SkIPoint::Make(state->layers[i].x,
michael@0:                                                              state->layers[i].y));
michael@0:     }
michael@0: 
michael@0:     return canvas.detach();
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: void SkCanvasStateUtils::ReleaseCanvasState(SkCanvasState* state) {
michael@0:     SkDELETE(state);
michael@0: }