Simplify draw one glyph

src/core/SkDraw.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #define __STDC_LIMIT_MACROS
 
 #include "SkDraw.h"
 #include "SkBlitter.h"
@@ skipping 1405 matching lines @@
     }
 }
 
 // disable warning : local variable used without having been initialized
 #if defined _WIN32 && _MSC_VER >= 1300
 #pragma warning ( push )
 #pragma warning ( disable : 4701 )
 #endif
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
-struct SkDraw1Glyph {
-    const SkDraw* fDraw;
-    const SkRegion* fClip;
-    const SkAAClip* fAAClip;
-    SkBlitter* fBlitter;
-    SkGlyphCache* fCache;
-    const SkPaint* fPaint;
-    SkIRect fClipBounds;
-    /** Half the sampling frequency of the rasterized glyph in x. */
-    SkScalar fHalfSampleX;
-    /** Half the sampling frequency of the rasterized glyph in y. */
-    SkScalar fHalfSampleY;
 
-    /** Draws one glyph.
-     *
-     *  The x and y are pre-biased, so implementations may just truncate them.
-     *  i.e. half the sampling frequency has been added.
-     *  e.g. 1/2 or 1/(2^(SkGlyph::kSubBits+1)) has already been added.
-     *  This added bias can be found in fHalfSampleX,Y.
-     */
-    typedef void (*Proc)(const SkDraw1Glyph&, Sk48Dot16 x, Sk48Dot16 y, const SkGlyph&);
+class DrawOneGlyph {
+public:
+    DrawOneGlyph(const SkDraw& draw, const SkPaint& paint, SkGlyphCache* cache, SkBlitter* blitter)
+        : fUseRegionToDraw(UsingRegionToDraw(draw.fRC))
+        , fGlyphCache(cache)
+        , fBlitter(blitter)
+        , fClip(fUseRegionToDraw ? &draw.fRC->bwRgn() : nullptr)
+        , fDraw(draw)
+        , fPaint(paint)
+        , fClipBounds(PickClipBounds(draw)) { }
 
-    Proc init(const SkDraw* draw, SkBlitter* blitter, SkGlyphCache* cache,
-              const SkPaint&);
+    void operator()(const SkGlyph& glyph, SkPoint position, SkPoint rounding) {
+        position += rounding;
+        Sk48Dot16 fx = SkScalarTo48Dot16(position.fX);
+        Sk48Dot16 fy = SkScalarTo48Dot16(position.fY);
+        // Prevent glyphs from being drawn outside of or straddling the edge of device space.
+        if ((fx >> 16) > INT_MAX - (INT16_MAX + UINT16_MAX) ||
+            (fx >> 16) < INT_MIN - (INT16_MIN + 0 /*UINT16_MIN*/) ||
+            (fy >> 16) > INT_MAX - (INT16_MAX + UINT16_MAX) ||
+            (fy >> 16) < INT_MIN - (INT16_MIN + 0 /*UINT16_MIN*/)) {
+            return;
+        }
 
-    // call this instead of fBlitter->blitMask() since this wrapper will handle
-    // the case when the mask is ARGB32_Format
-    //
+        int left = Sk48Dot16FloorToInt(fx);
+        int top  = Sk48Dot16FloorToInt(fy);
+        SkASSERT(glyph.fWidth > 0 && glyph.fHeight > 0);
+
+        left += glyph.fLeft;
+        top  += glyph.fTop;
+
+        int right   = left + glyph.fWidth;
+        int bottom  = top  + glyph.fHeight;
+
+        SkMask mask;
+        mask.fBounds.set(left, top, right, bottom);
+
+        if (fUseRegionToDraw) {
+            SkRegion::Cliperator clipper(*fClip, mask.fBounds);
+
+            if (!clipper.done() && this->getImageData(glyph, &mask)) {
+                const SkIRect& cr = clipper.rect();
+                do {
+                    this->blitMask(mask, cr);
+                    clipper.next();
+                } while (!clipper.done());
+            }
+        } else {
+            SkIRect  storage;
+            SkIRect* bounds = &mask.fBounds;
+
+            // this extra test is worth it, assuming that most of the time it succeeds
+            // since we can avoid writing to storage
+            if (!fClipBounds.containsNoEmptyCheck(mask.fBounds)) {
+                if (!storage.intersectNoEmptyCheck(mask.fBounds, fClipBounds))
+                    return;
+                bounds = &storage;
+            }
+
+            if (this->getImageData(glyph, &mask)) {
+                this->blitMask(mask, *bounds);
+            }
+        }
+    }
+
+private:
+    static bool UsingRegionToDraw(const SkRasterClip* rClip) {
+        return rClip->isBW() && !rClip->isRect();
+    }
+
+    static SkIRect PickClipBounds(const SkDraw& draw) {
+        const SkRasterClip& rasterClip = *draw.fRC;
+
+        if (rasterClip.isBW()) {
+            return rasterClip.bwRgn().getBounds();
+        } else {
+            return rasterClip.aaRgn().getBounds();
+        }
+    }
+
+    bool getImageData(const SkGlyph& glyph, SkMask* mask) {
+        uint8_t* bits = (uint8_t*)(fGlyphCache->findImage(glyph));
+        if (nullptr == bits) {
+            return false;  // can't rasterize glyph
+        }
+        mask->fImage    = bits;
+        mask->fRowBytes = glyph.rowBytes();
+        mask->fFormat   = static_cast<SkMask::Format>(glyph.fMaskFormat);
+        return true;
+    }
+
     void blitMask(const SkMask& mask, const SkIRect& clip) const {
         if (SkMask::kARGB32_Format == mask.fFormat) {
-            this->blitMaskAsSprite(mask);
+            SkBitmap bm;
+            bm.installPixels(
+                SkImageInfo::MakeN32Premul(mask.fBounds.width(), mask.fBounds.height()),
+                (SkPMColor*)mask.fImage, mask.fRowBytes);
+
+            fDraw.drawSprite(bm, mask.fBounds.x(), mask.fBounds.y(), fPaint);
         } else {
             fBlitter->blitMask(mask, clip);
         }
     }
 
-    // mask must be kARGB32_Format
-    void blitMaskAsSprite(const SkMask& mask) const;
+    const bool            fUseRegionToDraw;
+    SkGlyphCache  * const fGlyphCache;
+    SkBlitter     * const fBlitter;
+    const SkRegion* const fClip;
+    const SkDraw&         fDraw;
+    const SkPaint&        fPaint;
+    const SkIRect         fClipBounds;
 };
 
-static void D1G_RectClip(const SkDraw1Glyph& state, Sk48Dot16 fx, Sk48Dot16 fy,
-                         const SkGlyph& glyph) {
-    // Prevent glyphs from being drawn outside of or straddling the edge of device space.
-    if ((fx >> 16) > INT_MAX - (INT16_MAX + UINT16_MAX) ||
-        (fx >> 16) < INT_MIN - (INT16_MIN + 0 /*UINT16_MIN*/) ||
-        (fy >> 16) > INT_MAX - (INT16_MAX + UINT16_MAX) ||
-        (fy >> 16) < INT_MIN - (INT16_MIN + 0 /*UINT16_MIN*/))
-    {
-        return;
-    }
-
-    int left = Sk48Dot16FloorToInt(fx);
-    int top = Sk48Dot16FloorToInt(fy);
-    SkASSERT(glyph.fWidth > 0 && glyph.fHeight > 0);
-    SkASSERT((nullptr == state.fClip && state.fAAClip) ||
-             (state.fClip && nullptr == state.fAAClip && state.fClip->isRect()));
-
-    left += glyph.fLeft;
-    top  += glyph.fTop;
-
-    int right   = left + glyph.fWidth;
-    int bottom  = top + glyph.fHeight;
-
-    SkMask        mask;
-    SkIRect        storage;
-    SkIRect*    bounds = &mask.fBounds;
-
-    mask.fBounds.set(left, top, right, bottom);
-
-    // this extra test is worth it, assuming that most of the time it succeeds
-    // since we can avoid writing to storage
-    if (!state.fClipBounds.containsNoEmptyCheck(left, top, right, bottom)) {
-        if (!storage.intersectNoEmptyCheck(mask.fBounds, state.fClipBounds))
-            return;
-        bounds = &storage;
-    }
-
-    uint8_t* aa = (uint8_t*)glyph.fImage;
-    if (nullptr == aa) {
-        aa = (uint8_t*)state.fCache->findImage(glyph);
-        if (nullptr == aa) {
-            return; // can't rasterize glyph
-        }
-    }
-
-    mask.fRowBytes = glyph.rowBytes();
-    mask.fFormat = static_cast<SkMask::Format>(glyph.fMaskFormat);
-    mask.fImage = aa;
-    state.blitMask(mask, *bounds);
-}
-
-static void D1G_RgnClip(const SkDraw1Glyph& state, Sk48Dot16 fx, Sk48Dot16 fy,
-                        const SkGlyph& glyph) {
-    int left = Sk48Dot16FloorToInt(fx);
-    int top = Sk48Dot16FloorToInt(fy);
-    SkASSERT(glyph.fWidth > 0 && glyph.fHeight > 0);
-    SkASSERT(!state.fClip->isRect());
-
-    SkMask  mask;
-
-    left += glyph.fLeft;
-    top  += glyph.fTop;
-
-    mask.fBounds.set(left, top, left + glyph.fWidth, top + glyph.fHeight);
-    SkRegion::Cliperator clipper(*state.fClip, mask.fBounds);
-
-    if (!clipper.done()) {
-        const SkIRect&  cr = clipper.rect();
-        const uint8_t* aa = (uint8_t*)state.fCache->findImage(glyph);
-        if (nullptr == aa) {
-            return;
-        }
-
-        mask.fRowBytes = glyph.rowBytes();
-        mask.fFormat = static_cast<SkMask::Format>(glyph.fMaskFormat);
-        mask.fImage = (uint8_t*)aa;
-        do {
-            state.blitMask(mask, cr);
-            clipper.next();
-        } while (!clipper.done());
-    }
-}
-
-SkDraw1Glyph::Proc SkDraw1Glyph::init(const SkDraw* draw, SkBlitter* blitter, SkGlyphCache* cache,
-                                      const SkPaint& pnt) {
-    fDraw = draw;
-    fBlitter = blitter;
-    fCache = cache;
-    fPaint = &pnt;
-
-    if (cache->isSubpixel()) {
-        fHalfSampleX = fHalfSampleY = SkFixedToScalar(SkGlyph::kSubpixelRound);
-    } else {
-        fHalfSampleX = fHalfSampleY = SK_ScalarHalf;
-    }
-
-    if (draw->fRC->isBW()) {
-        fAAClip = nullptr;
-        fClip = &draw->fRC->bwRgn();
-        fClipBounds = fClip->getBounds();
-        if (fClip->isRect()) {
-            return D1G_RectClip;
-        } else {
-            return D1G_RgnClip;
-        }
-    } else {    // aaclip
-        fAAClip = &draw->fRC->aaRgn();
-        fClip = nullptr;
-        fClipBounds = fAAClip->getBounds();
-        return D1G_RectClip;
-    }
-}
-
-void SkDraw1Glyph::blitMaskAsSprite(const SkMask& mask) const {
-    SkASSERT(SkMask::kARGB32_Format == mask.fFormat);
-
-    SkBitmap bm;
-    bm.installPixels(SkImageInfo::MakeN32Premul(mask.fBounds.width(), mask.fBounds.height()),
-                     (SkPMColor*)mask.fImage, mask.fRowBytes);
-
-    fDraw->drawSprite(bm, mask.fBounds.x(), mask.fBounds.y(), *fPaint);
-}
-
-///////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////////////////////
 
 void SkDraw::drawText(const char text[], size_t byteLength,
                       SkScalar x, SkScalar y, const SkPaint& paint) const {
     SkASSERT(byteLength == 0 || text != nullptr);
 
     SkDEBUGCODE(this->validate();)
 
     // nothing to draw
     if (text == nullptr || byteLength == 0 || fRC->isEmpty()) {
         return;
     }
 
     // SkScalarRec doesn't currently have a way of representing hairline stroke and
     // will fill if its frame-width is 0.
     if (ShouldDrawTextAsPaths(paint, *fMatrix)) {
         this->drawText_asPaths(text, byteLength, x, y, paint);
         return;
     }
 
-    SkAutoGlyphCache    autoCache(paint, &fDevice->surfaceProps(), fMatrix);
-    SkGlyphCache*       cache = autoCache.getCache();
-
+    SkAutoGlyphCache       autoCache(paint, &fDevice->surfaceProps(), fMatrix);
+    SkGlyphCache*          cache = autoCache.getCache();
 
     // The Blitter Choose needs to be live while using the blitter below.
     SkAutoBlitterChoose    blitterChooser(fDst, *fMatrix, paint);
     SkAAClipBlitterWrapper wrapper(*fRC, blitterChooser.get());
-
-    SkDraw1Glyph        d1g;
-    SkDraw1Glyph::Proc  proc = d1g.init(this, wrapper.getBlitter(), cache, paint);
+    DrawOneGlyph           drawOneGlyph(*this, paint, cache, wrapper.getBlitter());
 
     SkFindAndPlaceGlyph::ProcessText(
         paint.getTextEncoding(), text, byteLength,
-        {x, y}, *fMatrix, paint.getTextAlign(), cache,
-        [&](const SkGlyph& glyph, SkPoint position, SkPoint rounding) {
-            position += rounding;
-            proc(d1g, SkScalarTo48Dot16(position.fX), SkScalarTo48Dot16(position.fY), glyph);
-        }
-    );
+        {x, y}, *fMatrix, paint.getTextAlign(), cache, drawOneGlyph);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
 void SkDraw::drawPosText_asPaths(const char text[], size_t byteLength,
                                  const SkScalar pos[], int scalarsPerPosition,
                                  const SkPoint& offset, const SkPaint& origPaint) const {
     // setup our std paint, in hopes of getting hits in the cache
     SkPaint paint(origPaint);
     SkScalar matrixScale = paint.setupForAsPaths();
@@ skipping 51 matching lines @@
     // nothing to draw
     if (text == nullptr || byteLength == 0 || fRC->isEmpty()) {
         return;
     }
 
     if (ShouldDrawTextAsPaths(paint, *fMatrix)) {
         this->drawPosText_asPaths(text, byteLength, pos, scalarsPerPosition, offset, paint);
         return;
     }
 
+    SkAutoGlyphCache       autoCache(paint, &fDevice->surfaceProps(), fMatrix);
+    SkGlyphCache*          cache = autoCache.getCache();
+
     // The Blitter Choose needs to be live while using the blitter below.
     SkAutoBlitterChoose    blitterChooser(fDst, *fMatrix, paint);
     SkAAClipBlitterWrapper wrapper(*fRC, blitterChooser.get());
-
-    SkAutoGlyphCache   autoCache(paint, &fDevice->surfaceProps(), fMatrix);
-    SkGlyphCache*      cache = autoCache.getCache();
-    SkDraw1Glyph       d1g;
-    SkDraw1Glyph::Proc proc = d1g.init(this, wrapper.getBlitter(), cache, paint);
-    SkPaint::Align     textAlignment = paint.getTextAlign();
+    DrawOneGlyph           drawOneGlyph(*this, paint, cache, wrapper.getBlitter());
+    SkPaint::Align         textAlignment = paint.getTextAlign();
 
     SkFindAndPlaceGlyph::ProcessPosText(
         paint.getTextEncoding(), text, byteLength,
-        offset, *fMatrix, pos, scalarsPerPosition, textAlignment, cache,
-        [&](const SkGlyph& glyph, SkPoint position, SkPoint rounding) {
-            position += rounding;
-            proc(d1g, SkScalarTo48Dot16(position.fX), SkScalarTo48Dot16(position.fY), glyph);
-        }
-    );
+        offset, *fMatrix, pos, scalarsPerPosition, textAlignment, cache, drawOneGlyph);
 }
 
 #if defined _WIN32 && _MSC_VER >= 1300
 #pragma warning ( pop )
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////
 
 static SkScan::HairRCProc ChooseHairProc(bool doAntiAlias) {
     return doAntiAlias ? SkScan::AntiHairLine : SkScan::HairLine;
@@ skipping 382 matching lines @@
         mask->fImage = SkMask::AllocImage(size);
         memset(mask->fImage, 0, mask->computeImageSize());
     }
 
     if (SkMask::kJustComputeBounds_CreateMode != mode) {
         draw_into_mask(*mask, devPath, style);
     }
 
     return true;
 }