android_frameworks_base/libs/hwui/SkiaCanvasProxy.cpp

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "SkiaCanvasProxy.h"

#include <cutils/log.h>
#include <SkPatchUtils.h>

namespace android {
namespace uirenderer {

SkiaCanvasProxy::SkiaCanvasProxy(Canvas* canvas)
        : INHERITED(canvas->width(), canvas->height())
        , mCanvas(canvas) {}

void SkiaCanvasProxy::onDrawPaint(const SkPaint& paint) {
    mCanvas->drawPaint(paint);
}

void SkiaCanvasProxy::onDrawPoints(PointMode pointMode, size_t count, const SkPoint pts[],
        const SkPaint& paint) {
    // convert the SkPoints into floats
    SK_COMPILE_ASSERT(sizeof(SkPoint) == sizeof(float)*2, SkPoint_is_no_longer_2_floats);
    const size_t floatCount = count << 1;
    const float* floatArray = &pts[0].fX;

    switch (pointMode) {
        case kPoints_PointMode: {
            mCanvas->drawPoints(floatArray, floatCount, paint);
            break;
        }
        case kLines_PointMode: {
            mCanvas->drawLines(floatArray, floatCount, paint);
            break;
        }
        case kPolygon_PointMode: {
            SkPaint strokedPaint(paint);
            strokedPaint.setStyle(SkPaint::kStroke_Style);

            SkPath path;
            for (size_t i = 0; i < count - 1; i++) {
                path.moveTo(pts[i]);
                path.lineTo(pts[i+1]);
                this->drawPath(path, strokedPaint);
                path.rewind();
            }
            break;
        }
        default:
            LOG_ALWAYS_FATAL("Unknown point type");
    }
}

void SkiaCanvasProxy::onDrawOval(const SkRect& rect, const SkPaint& paint) {
    mCanvas->drawOval(rect.fLeft, rect.fTop, rect.fRight, rect.fBottom, paint);
}

void SkiaCanvasProxy::onDrawRect(const SkRect& rect, const SkPaint& paint) {
    mCanvas->drawRect(rect.fLeft, rect.fTop, rect.fRight, rect.fBottom, paint);
}

void SkiaCanvasProxy::onDrawRRect(const SkRRect& roundRect, const SkPaint& paint) {
    if (!roundRect.isComplex()) {
        const SkRect& rect = roundRect.rect();
        SkVector radii = roundRect.getSimpleRadii();
        mCanvas->drawRoundRect(rect.fLeft, rect.fTop, rect.fRight, rect.fBottom,
                               radii.fX, radii.fY, paint);
    } else {
        SkPath path;
        path.addRRect(roundRect);
        mCanvas->drawPath(path, paint);
    }
}

void SkiaCanvasProxy::onDrawPath(const SkPath& path, const SkPaint& paint) {
    mCanvas->drawPath(path, paint);
}

void SkiaCanvasProxy::onDrawBitmap(const SkBitmap& bitmap, SkScalar left, SkScalar top,
        const SkPaint* paint) {
    mCanvas->drawBitmap(bitmap, left, top, paint);
}

void SkiaCanvasProxy::onDrawBitmapRect(const SkBitmap& bitmap, const SkRect* srcPtr,
        const SkRect& dst, const SkPaint* paint, DrawBitmapRectFlags) {
    SkRect src = (srcPtr) ? *srcPtr : SkRect::MakeWH(bitmap.width(), bitmap.height());
    mCanvas->drawBitmap(bitmap, src.fLeft, src.fTop, src.fRight, src.fBottom,
                        dst.fLeft, dst.fTop, dst.fRight, dst.fBottom, paint);
}

void SkiaCanvasProxy::onDrawBitmapNine(const SkBitmap& bitmap, const SkIRect& center,
        const SkRect& dst, const SkPaint*) {
    //TODO make nine-patch drawing a method on Canvas.h
    SkDEBUGFAIL("SkiaCanvasProxy::onDrawBitmapNine is not yet supported");
}

void SkiaCanvasProxy::onDrawSprite(const SkBitmap& bitmap, int left, int top,
        const SkPaint* paint) {
    mCanvas->save(SkCanvas::kMatrixClip_SaveFlag);
    mCanvas->setMatrix(SkMatrix::I());
    mCanvas->drawBitmap(bitmap, left, top, paint);
    mCanvas->restore();
}

void SkiaCanvasProxy::onDrawVertices(VertexMode mode, int vertexCount, const SkPoint vertices[],
        const SkPoint texs[], const SkColor colors[], SkXfermode*, const uint16_t indices[],
        int indexCount, const SkPaint& paint) {
    // convert the SkPoints into floats
    SK_COMPILE_ASSERT(sizeof(SkPoint) == sizeof(float)*2, SkPoint_is_no_longer_2_floats);
    const int floatCount = vertexCount << 1;
    const float* vArray = &vertices[0].fX;
    const float* tArray = (texs) ? &texs[0].fX : NULL;
    const int* cArray = (colors) ? (int*)colors : NULL;
    mCanvas->drawVertices(mode, floatCount, vArray, tArray, cArray, indices, indexCount, paint);
}

SkSurface* SkiaCanvasProxy::onNewSurface(const SkImageInfo&, const SkSurfaceProps&) {
    SkDEBUGFAIL("SkiaCanvasProxy::onNewSurface is not supported");
    return NULL;
}

void SkiaCanvasProxy::willSave() {
    mCanvas->save(SkCanvas::kMatrixClip_SaveFlag);
}

SkCanvas::SaveLayerStrategy SkiaCanvasProxy::willSaveLayer(const SkRect* rectPtr,
        const SkPaint* paint, SaveFlags flags) {
    SkRect rect;
    if (rectPtr) {
        rect = *rectPtr;
    } else if(!mCanvas->getClipBounds(&rect)) {
        rect = SkRect::MakeEmpty();
    }
    mCanvas->saveLayer(rect.fLeft, rect.fTop, rect.fRight, rect.fBottom, paint, flags);
    return SkCanvas::kNoLayer_SaveLayerStrategy;
}

void SkiaCanvasProxy::willRestore() {
    mCanvas->restore();
}

void SkiaCanvasProxy::didConcat(const SkMatrix& matrix) {
    mCanvas->concat(matrix);
}

void SkiaCanvasProxy::didSetMatrix(const SkMatrix& matrix) {
    mCanvas->setMatrix(matrix);
}

void SkiaCanvasProxy::onDrawDRRect(const SkRRect& outer, const SkRRect& inner,
        const SkPaint& paint) {
    SkPath path;
    path.addRRect(outer);
    path.addRRect(inner);
    path.setFillType(SkPath::kEvenOdd_FillType);
    this->drawPath(path, paint);
}

/**
 * Utility class that converts the incoming text & paint from the given encoding
 * into glyphIDs.
 */
class GlyphIDConverter {
public:
    GlyphIDConverter(const void* text, size_t byteLength, const SkPaint& origPaint) {
        paint = origPaint;
        if (paint.getTextEncoding() == SkPaint::kGlyphID_TextEncoding) {
            glyphIDs = (uint16_t*)text;
            count = byteLength >> 1;
        } else {
            storage.reset(byteLength); // ensures space for one glyph per ID given UTF8 encoding.
            glyphIDs = storage.get();
            count = paint.textToGlyphs(text, byteLength, storage.get());
            paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
        }
    }

    SkPaint paint;
    uint16_t* glyphIDs;
    int count;
private:
    SkAutoSTMalloc<32, uint16_t> storage;
};

void SkiaCanvasProxy::onDrawText(const void* text, size_t byteLength, SkScalar x, SkScalar y,
        const SkPaint& origPaint) {
    // convert to glyphIDs if necessary
    GlyphIDConverter glyphs(text, byteLength, origPaint);

    // compute the glyph positions
    SkAutoSTMalloc<32, SkPoint> pointStorage(glyphs.count);
    SkAutoSTMalloc<32, SkScalar> glyphWidths(glyphs.count);
    glyphs.paint.getTextWidths(glyphs.glyphIDs, glyphs.count << 1, glyphWidths.get());

    // compute conservative bounds
    // NOTE: We could call the faster paint.getFontBounds for a less accurate,
    //       but even more conservative bounds if this  is too slow.
    SkRect bounds;
    glyphs.paint.measureText(glyphs.glyphIDs, glyphs.count << 1, &bounds);

    // adjust for non-left alignment
    if (glyphs.paint.getTextAlign() != SkPaint::kLeft_Align) {
        SkScalar stop = 0;
        for (int i = 0; i < glyphs.count; i++) {
            stop += glyphWidths[i];
        }
        if (glyphs.paint.getTextAlign() == SkPaint::kCenter_Align) {
            stop = SkScalarHalf(stop);
        }
        if (glyphs.paint.isVerticalText()) {
            y -= stop;
        } else {
            x -= stop;
        }
    }

    // setup the first glyph position and adjust bounds if needed
    if (mCanvas->drawTextAbsolutePos()) {
        bounds.offset(x,y);
        pointStorage[0].set(x, y);
    } else {
        pointStorage[0].set(0, 0);
    }

    // setup the remaining glyph positions
    if (glyphs.paint.isVerticalText()) {
        for (int i = 1; i < glyphs.count; i++) {
            pointStorage[i].set(x, glyphWidths[i-1] + pointStorage[i-1].fY);
        }
    } else {
        for (int i = 1; i < glyphs.count; i++) {
            pointStorage[i].set(glyphWidths[i-1] + pointStorage[i-1].fX, y);
        }
    }

    SK_COMPILE_ASSERT(sizeof(SkPoint) == sizeof(float)*2, SkPoint_is_no_longer_2_floats);
    mCanvas->drawText(glyphs.glyphIDs, &pointStorage[0].fX, glyphs.count, glyphs.paint,
                      x, y, bounds.fLeft, bounds.fTop, bounds.fRight, bounds.fBottom, 0);
}

void SkiaCanvasProxy::onDrawPosText(const void* text, size_t byteLength, const SkPoint pos[],
        const SkPaint& origPaint) {
    // convert to glyphIDs if necessary
    GlyphIDConverter glyphs(text, byteLength, origPaint);

    // convert to relative positions if necessary
    int x, y;
    const SkPoint* posArray;
    SkAutoSTMalloc<32, SkPoint> pointStorage;
    if (mCanvas->drawTextAbsolutePos()) {
        x = 0;
        y = 0;
        posArray = pos;
    } else {
        x = pos[0].fX;
        y = pos[0].fY;
        posArray = pointStorage.reset(glyphs.count);
        for (int i = 0; i < glyphs.count; i++) {
            pointStorage[i].fX = pos[i].fX- x;
            pointStorage[i].fY = pos[i].fY- y;
        }
    }

    // compute conservative bounds
    // NOTE: We could call the faster paint.getFontBounds for a less accurate,
    //       but even more conservative bounds if this  is too slow.
    SkRect bounds;
    glyphs.paint.measureText(glyphs.glyphIDs, glyphs.count << 1, &bounds);

    SK_COMPILE_ASSERT(sizeof(SkPoint) == sizeof(float)*2, SkPoint_is_no_longer_2_floats);
    mCanvas->drawText(glyphs.glyphIDs, &posArray[0].fX, glyphs.count, glyphs.paint, x, y,
                      bounds.fLeft, bounds.fTop, bounds.fRight, bounds.fBottom, 0);
}

void SkiaCanvasProxy::onDrawPosTextH(const void* text, size_t byteLength, const SkScalar xpos[],
        SkScalar constY, const SkPaint& paint) {
    const size_t pointCount = byteLength >> 1;
    SkAutoSTMalloc<32, SkPoint> storage(pointCount);
    SkPoint* pts = storage.get();
    for (size_t i = 0; i < pointCount; i++) {
        pts[i].set(xpos[i], constY);
    }
    this->onDrawPosText(text, byteLength, pts, paint);
}

void SkiaCanvasProxy::onDrawTextOnPath(const void* text, size_t byteLength, const SkPath& path,
        const SkMatrix* matrix, const SkPaint& origPaint) {
    // convert to glyphIDs if necessary
    GlyphIDConverter glyphs(text, byteLength, origPaint);
    mCanvas->drawTextOnPath(glyphs.glyphIDs, glyphs.count, path, 0, 0, glyphs.paint);
}

void SkiaCanvasProxy::onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y,
        const SkPaint& paint) {
    SkDEBUGFAIL("SkiaCanvasProxy::onDrawTextBlob is not supported");
}

void SkiaCanvasProxy::onDrawPatch(const SkPoint cubics[12], const SkColor colors[4],
        const SkPoint texCoords[4], SkXfermode* xmode, const SkPaint& paint) {
    SkPatchUtils::VertexData data;

    SkMatrix matrix;
    mCanvas->getMatrix(&matrix);
    SkISize lod = SkPatchUtils::GetLevelOfDetail(cubics, &matrix);

    // It automatically adjusts lodX and lodY in case it exceeds the number of indices.
    // If it fails to generate the vertices, then we do not draw.
    if (SkPatchUtils::getVertexData(&data, cubics, colors, texCoords, lod.width(), lod.height())) {
        this->drawVertices(SkCanvas::kTriangles_VertexMode, data.fVertexCount, data.fPoints,
                           data.fTexCoords, data.fColors, xmode, data.fIndices, data.fIndexCount,
                           paint);
    }
}

void SkiaCanvasProxy::onClipRect(const SkRect& rect, SkRegion::Op op, ClipEdgeStyle) {
    mCanvas->clipRect(rect.fLeft, rect.fTop, rect.fRight, rect.fBottom, op);
}

void SkiaCanvasProxy::onClipRRect(const SkRRect& roundRect, SkRegion::Op op, ClipEdgeStyle) {
    SkPath path;
    path.addRRect(roundRect);
    mCanvas->clipPath(&path, op);
}

void SkiaCanvasProxy::onClipPath(const SkPath& path, SkRegion::Op op, ClipEdgeStyle) {
    mCanvas->clipPath(&path, op);
}

void SkiaCanvasProxy::onClipRegion(const SkRegion& region, SkRegion::Op op) {
    mCanvas->clipRegion(&region, op);
}

}; // namespace uirenderer
}; // namespace android