src/gpu/GrTextUtils.cpp

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrTextUtils.h"

#include "GrBlurUtils.h"
#include "GrContext.h"
#include "GrDrawContext.h"
#include "SkDrawProcs.h"
#include "SkGlyphCache.h"
#include "SkPaint.h"
#include "SkRect.h"
#include "SkTextMapStateProc.h"
#include "SkTextToPathIter.h"

void GrTextUtils::DrawTextAsPath(GrContext* context, GrDrawContext* dc,
                                 const GrClip& clip,
                                 const SkPaint& skPaint, const SkMatrix& viewMatrix,
                                 const char text[], size_t byteLength, SkScalar x, SkScalar y,
                                 const SkIRect& clipBounds) {
    SkTextToPathIter iter(text, byteLength, skPaint, true);

    SkMatrix    matrix;
    matrix.setScale(iter.getPathScale(), iter.getPathScale());
    matrix.postTranslate(x, y);

    const SkPath* iterPath;
    SkScalar xpos, prevXPos = 0;

    while (iter.next(&iterPath, &xpos)) {
        matrix.postTranslate(xpos - prevXPos, 0);
        if (iterPath) {
            const SkPaint& pnt = iter.getPaint();
            GrBlurUtils::drawPathWithMaskFilter(context, dc, clip, *iterPath,
                                                pnt, viewMatrix, &matrix, clipBounds, false);
        }
        prevXPos = xpos;
    }
}

void GrTextUtils::DrawPosTextAsPath(GrContext* context,
                                    GrDrawContext* dc,
                                    const SkSurfaceProps& props,
                                    const GrClip& clip,
                                    const SkPaint& origPaint, const SkMatrix& viewMatrix,
                                    const char text[], size_t byteLength,
                                    const SkScalar pos[], int scalarsPerPosition,
                                    const SkPoint& offset, const SkIRect& clipBounds) {
    // setup our std paint, in hopes of getting hits in the cache
    SkPaint paint(origPaint);
    SkScalar matrixScale = paint.setupForAsPaths();

    SkMatrix matrix;
    matrix.setScale(matrixScale, matrixScale);

    // Temporarily jam in kFill, so we only ever ask for the raw outline from the cache.
    paint.setStyle(SkPaint::kFill_Style);
    paint.setPathEffect(nullptr);

    SkDrawCacheProc     glyphCacheProc = paint.getDrawCacheProc();
    SkAutoGlyphCache    autoCache(paint, &props, nullptr);
    SkGlyphCache*       cache = autoCache.getCache();

    const char*        stop = text + byteLength;
    SkTextAlignProc    alignProc(paint.getTextAlign());
    SkTextMapStateProc tmsProc(SkMatrix::I(), offset, scalarsPerPosition);

    // Now restore the original settings, so we "draw" with whatever style/stroking.
    paint.setStyle(origPaint.getStyle());
    paint.setPathEffect(origPaint.getPathEffect());

    while (text < stop) {
        const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
        if (glyph.fWidth) {
            const SkPath* path = cache->findPath(glyph);
            if (path) {
                SkPoint tmsLoc;
                tmsProc(pos, &tmsLoc);
                SkPoint loc;
                alignProc(tmsLoc, glyph, &loc);

                matrix[SkMatrix::kMTransX] = loc.fX;
                matrix[SkMatrix::kMTransY] = loc.fY;
                GrBlurUtils::drawPathWithMaskFilter(context, dc, clip, *path, paint,
                                                    viewMatrix, &matrix, clipBounds, false);
            }
        }
        pos += scalarsPerPosition;
    }
}