SkGlyphRunListPainterCPU Class Reference

#include <SkGlyphRunPainter.h>

Classes
class	BitmapDevicePainter

Public Member Functions
	SkGlyphRunListPainterCPU (const SkSurfaceProps &props, SkColorType colorType, SkColorSpace *cs)
void	drawForBitmapDevice (SkCanvas *canvas, const BitmapDevicePainter *bitmapDevice, const sktext::GlyphRunList &glyphRunList, const SkPaint &paint, const SkMatrix &drawMatrix)

Detailed Description

Definition at line 29 of file SkGlyphRunPainter.h.

Constructor & Destructor Documentation

SkGlyphRunListPainterCPU()

SkGlyphRunListPainterCPU::SkGlyphRunListPainterCPU	(	const SkSurfaceProps &	props,
		SkColorType	colorType,
		SkColorSpace *	cs
	)

Definition at line 166 of file SkGlyphRunPainter.cpp.

        : fDeviceProps{props}
        , fBitmapFallbackProps{props.cloneWithPixelGeometry(kUnknown_SkPixelGeometry)}
        , fColorType{colorType}
        , fScalerContextFlags{compute_scaler_context_flags(cs)} {}

Member Function Documentation

drawForBitmapDevice()

void SkGlyphRunListPainterCPU::drawForBitmapDevice	(	SkCanvas *	canvas,
		const BitmapDevicePainter *	bitmapDevice,
		const sktext::GlyphRunList &	glyphRunList,
		const SkPaint &	paint,
		const SkMatrix &	drawMatrix
	)

Definition at line 174 of file SkGlyphRunPainter.cpp.

                                                                               {
    STArray<64, const SkGlyph*> acceptedPackedGlyphIDs;
    STArray<64, SkPoint> acceptedPositions;
    STArray<64, SkGlyphID> rejectedGlyphIDs;
    STArray<64, SkPoint> rejectedPositions;
    const int maxGlyphRunSize = glyphRunList.maxGlyphRunSize();
    acceptedPackedGlyphIDs.resize(maxGlyphRunSize);
    acceptedPositions.resize(maxGlyphRunSize);
    const auto acceptedBuffer = SkMakeZip(acceptedPackedGlyphIDs, acceptedPositions);
    rejectedGlyphIDs.resize(maxGlyphRunSize);
    rejectedPositions.resize(maxGlyphRunSize);
    const auto rejectedBuffer = SkMakeZip(rejectedGlyphIDs, rejectedPositions);
 
    // The bitmap blitters can only draw lcd text to a N32 bitmap in srcOver. Otherwise,
    // convert the lcd text into A8 text. The props communicate this to the scaler.
    auto& props = (kN32_SkColorType == fColorType && paint.isSrcOver())
                          ? fDeviceProps
                          : fBitmapFallbackProps;
 
    SkPoint drawOrigin = glyphRunList.origin();
    SkMatrix positionMatrix{drawMatrix};
    positionMatrix.preTranslate(drawOrigin.x(), drawOrigin.y());
    for (auto& glyphRun : glyphRunList) {
        const SkFont& runFont = glyphRun.font();
 
        SkZip<const SkGlyphID, const SkPoint> source = glyphRun.source();
 
        if (SkStrikeSpec::ShouldDrawAsPath(paint, runFont, positionMatrix)) {
            auto [strikeSpec, strikeToSourceScale] =
                    SkStrikeSpec::MakePath(runFont, paint, props, fScalerContextFlags);
 
            auto strike = strikeSpec.findOrCreateStrike();
 
            {
                auto [accepted, rejected] = prepare_for_path_drawing(strike.get(),
                                                                     source,
                                                                     acceptedBuffer,
                                                                     rejectedBuffer);
 
                source = rejected;
                // The paint we draw paths with must have the same anti-aliasing state as the
                // runFont allowing the paths to have the same edging as the glyph masks.
                SkPaint pathPaint = paint;
                pathPaint.setAntiAlias(runFont.hasSomeAntiAliasing());
 
                const bool stroking = pathPaint.getStyle() != SkPaint::kFill_Style;
                const bool hairline = pathPaint.getStrokeWidth() == 0;
                const bool needsExactCTM = pathPaint.getShader()     ||
                                           pathPaint.getPathEffect() ||
                                           pathPaint.getMaskFilter() ||
                                           (stroking && !hairline);
 
                if (!needsExactCTM) {
                    for (auto [glyph, pos] : accepted) {
                        const SkPath* path = glyph->path();
                        SkMatrix m;
                        SkPoint translate = drawOrigin + pos;
                        m.setScaleTranslate(strikeToSourceScale, strikeToSourceScale,
                                            translate.x(), translate.y());
                        SkAutoCanvasRestore acr(canvas, true);
                        canvas->concat(m);
                        canvas->drawPath(*path, pathPaint);
                    }
                } else {
                    for (auto [glyph, pos] : accepted) {
                        const SkPath* path = glyph->path();
                        SkMatrix m;
                        SkPoint translate = drawOrigin + pos;
                        m.setScaleTranslate(strikeToSourceScale, strikeToSourceScale,
                                            translate.x(), translate.y());
 
                        SkPath deviceOutline;
                        path->transform(m, &deviceOutline);
                        deviceOutline.setIsVolatile(true);
                        canvas->drawPath(deviceOutline, pathPaint);
                    }
                }
            }
 
            if (!source.empty()) {
                auto [accepted, rejected] = prepare_for_drawable_drawing(strike.get(),
                                                                         source,
                                                                         acceptedBuffer,
                                                                         rejectedBuffer);
                source = rejected;
 
                for (auto [glyph, pos] : accepted) {
                    SkDrawable* drawable = glyph->drawable();
                    SkMatrix m;
                    SkPoint translate = drawOrigin + pos;
                    m.setScaleTranslate(strikeToSourceScale, strikeToSourceScale,
                                        translate.x(), translate.y());
                    SkAutoCanvasRestore acr(canvas, false);
                    SkRect drawableBounds = drawable->getBounds();
                    m.mapRect(&drawableBounds);
                    canvas->saveLayer(&drawableBounds, &paint);
                    drawable->draw(canvas, &m);
                }
            }
        }
        if (!source.empty() && !positionMatrix.hasPerspective()) {
            SkStrikeSpec strikeSpec = SkStrikeSpec::MakeMask(
                    runFont, paint, props, fScalerContextFlags, positionMatrix);
 
            auto strike = strikeSpec.findOrCreateStrike();
 
            auto [accepted, rejected] = prepare_for_direct_mask_drawing(strike.get(),
                                                                        positionMatrix,
                                                                        source,
                                                                        acceptedBuffer,
                                                                        rejectedBuffer);
            source = rejected;
            bitmapDevice->paintMasks(accepted, paint);
        }
        if (!source.empty()) {
            std::vector<SkPoint> sourcePositions;
 
            // Create a strike is source space to calculate scale information.
            SkStrikeSpec scaleStrikeSpec = SkStrikeSpec::MakeMask(
                    runFont, paint, props, fScalerContextFlags, SkMatrix::I());
            SkBulkGlyphMetrics metrics{scaleStrikeSpec};
 
            auto glyphIDs = source.get<0>();
            auto positions = source.get<1>();
            SkSpan<const SkGlyph*> glyphs = metrics.glyphs(glyphIDs);
            SkScalar maxScale = SK_ScalarMin;
 
            // Calculate the scale that makes the longest edge 1:1 with its side in the cache.
            for (auto [glyph, pos] : SkMakeZip(glyphs, positions)) {
                if (glyph->isEmpty()) {
                    continue;
                }
                SkPoint corners[4];
                SkPoint srcPos = pos + drawOrigin;
                // Store off the positions in device space to position the glyphs during drawing.
                sourcePositions.push_back(srcPos);
                SkRect rect = glyph->rect();
                rect.makeOffset(srcPos);
                positionMatrix.mapRectToQuad(corners, rect);
                // left top -> right top
                SkScalar scale = (corners[1] - corners[0]).length() / rect.width();
                maxScale = std::max(maxScale, scale);
                // right top -> right bottom
                scale = (corners[2] - corners[1]).length() / rect.height();
                maxScale = std::max(maxScale, scale);
                // right bottom -> left bottom
                scale = (corners[3] - corners[2]).length() / rect.width();
                maxScale = std::max(maxScale, scale);
                // left bottom -> left top
                scale = (corners[0] - corners[3]).length() / rect.height();
                maxScale = std::max(maxScale, scale);
            }
 
            if (maxScale <= 0) {
                continue;  // to the next run.
            }
 
            if (maxScale * runFont.getSize() > 256) {
                maxScale = 256.0f / runFont.getSize();
            }
 
            SkMatrix cacheScale = SkMatrix::Scale(maxScale, maxScale);
            SkStrikeSpec strikeSpec = SkStrikeSpec::MakeMask(
                    runFont, paint, props, fScalerContextFlags, cacheScale);
 
            auto strike = strikeSpec.findOrCreateStrike();
 
            auto [accepted, rejected] = prepare_for_direct_mask_drawing(strike.get(),
                                                                        positionMatrix,
                                                                        source,
                                                                        acceptedBuffer,
                                                                        rejectedBuffer);
            const SkScalar invMaxScale = 1.0f/maxScale;
            for (auto [glyph, srcPos] : SkMakeZip(accepted.get<0>(), sourcePositions)) {
                SkMask mask = glyph->mask();
                // TODO: is this needed will A8 and BW just work?
                if (mask.fFormat != SkMask::kARGB32_Format) {
                    continue;
                }
                SkBitmap bm;
                bm.installPixels(SkImageInfo::MakeN32Premul(mask.fBounds.size()),
                                 const_cast<uint8_t*>(mask.fImage),
                                 mask.fRowBytes);
                bm.setImmutable();
 
                // Since the glyph in the cache is scaled by maxScale, its top left vector is too
                // long. Reduce it to find proper positions on the device.
                SkPoint realPos =
                    srcPos + SkPoint::Make(mask.fBounds.left(), mask.fBounds.top())*invMaxScale;
 
                // Calculate the preConcat matrix for drawBitmap to get the rectangle from the
                // glyph cache (which is multiplied by maxScale) to land in the right place.
                SkMatrix translate = SkMatrix::Translate(realPos);
                translate.preScale(invMaxScale, invMaxScale);
 
                // Draw the bitmap using the rect from the scaled cache, and not the source
                // rectangle for the glyph.
                bitmapDevice->drawBitmap(bm, translate, nullptr, SkFilterMode::kLinear, paint);
            }
        }
 
        // TODO: have the mask stage above reject the glyphs that are too big, and handle the
        //  rejects in a more sophisticated stage.
    }
}

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The documentation for this class was generated from the following files:

• third_party/skia/src/core/SkGlyphRunPainter.h
• third_party/skia/src/core/SkGlyphRunPainter.cpp