Extract "text align proc" functions as reusable classes

src/gpu/GrBitmapTextContext.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBitmapTextContext.h"
 #include "GrAtlas.h"
 #include "GrDrawTarget.h"
 #include "GrFontScaler.h"
 #include "GrIndexBuffer.h"
 #include "GrTextStrike.h"
 #include "GrTextStrike_impl.h"
 #include "SkColorPriv.h"
 #include "SkPath.h"
 #include "SkRTConf.h"
 #include "SkStrokeRec.h"
 #include "effects/GrCustomCoordsTextureEffect.h"
 
 #include "SkAutoKern.h"
 #include "SkDraw.h"
+#include "SkDrawProcs.h"
 #include "SkGlyphCache.h"
 #include "SkGpuDevice.h"
 #include "SkGr.h"
+#include "SkTextMapStateProc.h"
 
 SK_CONF_DECLARE(bool, c_DumpFontCache, "gpu.dumpFontCache", false,
                 "Dump the contents of the font cache before every purge.");
 
 static const int kGlyphCoordsNoColorAttributeIndex = 1;
 static const int kGlyphCoordsWithColorAttributeIndex = 2;
 
 namespace {
 // position + texture coord
 extern const GrVertexAttrib gTextVertexAttribs[] = {
@@ skipping 220 matching lines @@
                                   fontScaler);
         }
 
         fx += glyph.fAdvanceX;
         fy += glyph.fAdvanceY;
     }
 
     this->finish();
 }
 
-///////////////////////////////////////////////////////////////////////////////
-// Copied from SkDraw
-
-// last parameter is interpreted as SkFixed [x, y]
-// return the fixed position, which may be rounded or not by the caller
-//   e.g. subpixel doesn't round
-typedef void (*AlignProc)(const SkPoint&, const SkGlyph&, SkIPoint*);
-
-static void leftAlignProc(const SkPoint& loc, const SkGlyph& glyph, SkIPoint* dst) {
-    dst->set(SkScalarToFixed(loc.fX), SkScalarToFixed(loc.fY));
-}
-
-static void centerAlignProc(const SkPoint& loc, const SkGlyph& glyph, SkIPoint* dst) {
-    dst->set(SkScalarToFixed(loc.fX) - (glyph.fAdvanceX >> 1),
-             SkScalarToFixed(loc.fY) - (glyph.fAdvanceY >> 1));
-}
-
-static void rightAlignProc(const SkPoint& loc, const SkGlyph& glyph, SkIPoint* dst) {
-    dst->set(SkScalarToFixed(loc.fX) - glyph.fAdvanceX,
-             SkScalarToFixed(loc.fY) - glyph.fAdvanceY);
-}
-
-static AlignProc pick_align_proc(SkPaint::Align align) {
-    static const AlignProc gProcs[] = {
-        leftAlignProc, centerAlignProc, rightAlignProc
-    };
-
-    SkASSERT((unsigned)align < SK_ARRAY_COUNT(gProcs));
-
-    return gProcs[align];
-}
-
-class BitmapTextMapState {
-public:
-    mutable SkPoint fLoc;
-
-    BitmapTextMapState(const SkMatrix& matrix, SkScalar y)
-        : fMatrix(matrix), fProc(matrix.getMapXYProc()), fY(y) {}
-
-    typedef void (*Proc)(const BitmapTextMapState&, const SkScalar pos[]);
-
-    Proc pickProc(int scalarsPerPosition);
-
-private:
-    const SkMatrix&     fMatrix;
-    SkMatrix::MapXYProc fProc;
-    SkScalar            fY; // ignored by MapXYProc
-    // these are only used by Only... procs
-    SkScalar            fScaleX, fTransX, fTransformedY;
-
-    static void MapXProc(const BitmapTextMapState& state, const SkScalar pos[]) {
-        state.fProc(state.fMatrix, *pos, state.fY, &state.fLoc);
-    }
-
-    static void MapXYProc(const BitmapTextMapState& state, const SkScalar pos[]) {
-        state.fProc(state.fMatrix, pos[0], pos[1], &state.fLoc);
-    }
-
-    static void MapOnlyScaleXProc(const BitmapTextMapState& state,
-                                  const SkScalar pos[]) {
-        state.fLoc.set(SkScalarMul(state.fScaleX, *pos) + state.fTransX,
-                       state.fTransformedY);
-    }
-
-    static void MapOnlyTransXProc(const BitmapTextMapState& state,
-                                  const SkScalar pos[]) {
-        state.fLoc.set(*pos + state.fTransX, state.fTransformedY);
-    }
-};
-
-BitmapTextMapState::Proc BitmapTextMapState::pickProc(int scalarsPerPosition) {
-    SkASSERT(1 == scalarsPerPosition || 2 == scalarsPerPosition);
-
-    if (1 == scalarsPerPosition) {
-        unsigned mtype = fMatrix.getType();
-        if (mtype & (SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask)) {
-            return MapXProc;
-        } else {
-            fScaleX = fMatrix.getScaleX();
-            fTransX = fMatrix.getTranslateX();
-            fTransformedY = SkScalarMul(fY, fMatrix.getScaleY()) +
-                            fMatrix.getTranslateY();
-            return (mtype & SkMatrix::kScale_Mask) ?
-                        MapOnlyScaleXProc : MapOnlyTransXProc;
-        }
-    } else {
-        return MapXYProc;
-    }
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
 void GrBitmapTextContext::drawPosText(const GrPaint& paint, const SkPaint& skPaint,
                                       const char text[], size_t byteLength,
                                       const SkScalar pos[], SkScalar constY,
                                       int scalarsPerPosition) {
     SkASSERT(byteLength == 0 || text != NULL);
     SkASSERT(1 == scalarsPerPosition || 2 == scalarsPerPosition);
 
     // nothing to draw
     if (text == NULL || byteLength == 0/* || fRC->isEmpty()*/) {
         return;
     }
 
     this->init(paint, skPaint);
 
     SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
 
     SkAutoGlyphCache    autoCache(fSkPaint, &fDeviceProperties, &fContext->getMatrix());
     SkGlyphCache*       cache = autoCache.getCache();
     GrFontScaler*       fontScaler = GetGrFontScaler(cache);
 
     // store original matrix before we reset, so we can use it to transform positions
     SkMatrix ctm = fContext->getMatrix();
     GrContext::AutoMatrix  autoMatrix;
     autoMatrix.setIdentity(fContext, &fPaint);
 
     const char*        stop = text + byteLength;
-    AlignProc          alignProc = pick_align_proc(fSkPaint.getTextAlign());
-    BitmapTextMapState       tms(ctm, constY);
-    BitmapTextMapState::Proc tmsProc = tms.pickProc(scalarsPerPosition);
+    SkTextAlignProc    alignProc(fSkPaint.getTextAlign());
+    SkTextMapStateProc tmsProc(ctm, constY, scalarsPerPosition);
     SkFixed halfSampleX = 0, halfSampleY = 0;
 
     if (cache->isSubpixel()) {
         // maybe we should skip the rounding if linearText is set
         SkAxisAlignment baseline = SkComputeAxisAlignmentForHText(ctm);
 
         SkFixed fxMask = ~0;
         SkFixed fyMask = ~0;
         if (kX_SkAxisAlignment == baseline) {
             fyMask = 0;
 #ifndef SK_IGNORE_SUBPIXEL_AXIS_ALIGN_FIX
             halfSampleY = SK_FixedHalf;
 #endif
         } else if (kY_SkAxisAlignment == baseline) {
             fxMask = 0;
 #ifndef SK_IGNORE_SUBPIXEL_AXIS_ALIGN_FIX
             halfSampleX = SK_FixedHalf;
 #endif
         }
 
         if (SkPaint::kLeft_Align == fSkPaint.getTextAlign()) {
             while (text < stop) {
-                tmsProc(tms, pos);
-                SkFixed fx = SkScalarToFixed(tms.fLoc.fX) + halfSampleX;
-                SkFixed fy = SkScalarToFixed(tms.fLoc.fY) + halfSampleY;
+                SkPoint tmsLoc;
+                tmsProc(pos, &tmsLoc);
+                SkFixed fx = SkScalarToFixed(tmsLoc.fX) + halfSampleX;
+                SkFixed fy = SkScalarToFixed(tmsLoc.fY) + halfSampleY;
 
                 const SkGlyph& glyph = glyphCacheProc(cache, &text,
                                                       fx & fxMask, fy & fyMask);
 
                 if (glyph.fWidth) {
                     this->drawPackedGlyph(GrGlyph::Pack(glyph.getGlyphID(),
                                                         glyph.getSubXFixed(),
                                                         glyph.getSubYFixed()),
                                           SkFixedFloorToFixed(fx),
                                           SkFixedFloorToFixed(fy),
                                           fontScaler);
                 }
                 pos += scalarsPerPosition;
             }
         } else {
             while (text < stop) {
                 const char* currentText = text;
                 const SkGlyph& metricGlyph = glyphCacheProc(cache, &text, 0, 0);
 
                 if (metricGlyph.fWidth) {
                     SkDEBUGCODE(SkFixed prevAdvX = metricGlyph.fAdvanceX;)
                     SkDEBUGCODE(SkFixed prevAdvY = metricGlyph.fAdvanceY;)
-
-                    tmsProc(tms, pos);
+                    SkPoint tmsLoc;
+                    tmsProc(pos, &tmsLoc);
                     SkIPoint fixedLoc;
-                    alignProc(tms.fLoc, metricGlyph, &fixedLoc);
+                    alignProc(tmsLoc, metricGlyph, &fixedLoc);
 
                     SkFixed fx = fixedLoc.fX + halfSampleX;
                     SkFixed fy = fixedLoc.fY + halfSampleY;
 
                     // have to call again, now that we've been "aligned"
                     const SkGlyph& glyph = glyphCacheProc(cache, &currentText,
                                                           fx & fxMask, fy & fyMask);
                     // the assumption is that the metrics haven't changed
                     SkASSERT(prevAdvX == glyph.fAdvanceX);
                     SkASSERT(prevAdvY == glyph.fAdvanceY);
@@ skipping 10 matching lines @@
             }
         }
     } else {    // not subpixel
 
         if (SkPaint::kLeft_Align == fSkPaint.getTextAlign()) {
             while (text < stop) {
                 // the last 2 parameters are ignored
                 const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
 
                 if (glyph.fWidth) {
-                    tmsProc(tms, pos);
+                    SkPoint tmsLoc;
+                    tmsProc(pos, &tmsLoc);
 
-                    SkFixed fx = SkScalarToFixed(tms.fLoc.fX) + SK_FixedHalf; //halfSampleX;
-                    SkFixed fy = SkScalarToFixed(tms.fLoc.fY) + SK_FixedHalf; //halfSampleY;
+                    SkFixed fx = SkScalarToFixed(tmsLoc.fX) + SK_FixedHalf; //halfSampleX;
+                    SkFixed fy = SkScalarToFixed(tmsLoc.fY) + SK_FixedHalf; //halfSampleY;
                     this->drawPackedGlyph(GrGlyph::Pack(glyph.getGlyphID(),
                                                         glyph.getSubXFixed(),
                                                         glyph.getSubYFixed()),
                                           SkFixedFloorToFixed(fx),
                                           SkFixedFloorToFixed(fy),
                                           fontScaler);
                 }
                 pos += scalarsPerPosition;
             }
         } else {
             while (text < stop) {
                 // the last 2 parameters are ignored
                 const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
 
                 if (glyph.fWidth) {
-                    tmsProc(tms, pos);
+                    SkPoint tmsLoc;
+                    tmsProc(pos, &tmsLoc);
 
                     SkIPoint fixedLoc;
-                    alignProc(tms.fLoc, glyph, &fixedLoc);
+                    alignProc(tmsLoc, glyph, &fixedLoc);
 
                     SkFixed fx = fixedLoc.fX + SK_FixedHalf; //halfSampleX;
                     SkFixed fy = fixedLoc.fY + SK_FixedHalf; //halfSampleY;
                     this->drawPackedGlyph(GrGlyph::Pack(glyph.getGlyphID(),
                                                         glyph.getSubXFixed(),
                                                         glyph.getSubYFixed()),
                                           SkFixedFloorToFixed(fx),
                                           SkFixedFloorToFixed(fy),
                                           fontScaler);
                 }
@@ skipping 178 matching lines @@
     if (useColorVerts) {
         // color comes after position.
         GrColor* colors = reinterpret_cast<GrColor*>(positions + 1);
         for (int i = 0; i < 4; ++i) {
            *colors = fPaint.getColor();
            colors = reinterpret_cast<GrColor*>(reinterpret_cast<intptr_t>(colors) + vertSize);
         }
     }
     fCurrVertex += 4;
 }