[QFontEngineFT] Consolidate .*lpha.*MapForGlyph() behavior

...and decrease code duplication.

Change-Id: I5eb3c0694dde9030405a3bd3d410ff9784ed7717
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 52 insertions, 71 deletions

diff --git a/src/gui/text/qfontengine_ft.cpp b/src/gui/text/qfontengine_ft.cpp
index 8176ede994..03b9e6ef99 100644
--- a/src/gui/text/qfontengine_ft.cpp
+++ b/src/gui/text/qfontengine_ft.cpp
@@ -1725,6 +1725,33 @@ glyph_metrics_t QFontEngineFT::alphaMapBoundingBox(glyph_t glyph, QFixed subPixe
     return overall;
 }
 
+static inline QImage alphaMapFromGlyphData(QFontEngineFT::Glyph *glyph, QFontEngine::GlyphFormat glyphFormat)
+{
+    if (glyph == Q_NULLPTR)
+        return QImage();
+
+    QImage::Format format;
+    int bytesPerLine;
+    switch (glyphFormat) {
+    case QFontEngine::Format_Mono:
+        format = QImage::Format_Mono;
+        bytesPerLine = ((glyph->width + 31) & ~31) >> 3;
+        break;
+    case QFontEngine::Format_A8:
+        format = QImage::Format_Alpha8;
+        bytesPerLine = (glyph->width + 3) & ~3;
+        break;
+    case QFontEngine::Format_A32:
+        format = QImage::Format_ARGB32;
+        bytesPerLine = glyph->width * 4;
+        break;
+    default:
+        Q_UNREACHABLE();
+    };
+
+    return QImage(static_cast<const uchar *>(glyph->data), glyph->width, glyph->height, bytesPerLine, format);
+}
+
 QImage *QFontEngineFT::lockedAlphaMapForGlyph(glyph_t glyphIndex, QFixed subPixelPosition,
                                               QFontEngine::GlyphFormat neededFormat,
                                               const QTransform &t, QPoint *offset)
@@ -1739,22 +1766,6 @@ QImage *QFontEngineFT::lockedAlphaMapForGlyph(glyph_t glyphIndex, QFixed subPixe
     else if (neededFormat == Format_None)
         neededFormat = Format_A8;
 
-    QImage::Format format;
-    switch (neededFormat) {
-    case Format_Mono:
-        format = QImage::Format_Mono;
-        break;
-    case Format_A8:
-        format = QImage::Format_Alpha8;
-        break;
-    case Format_A32:
-        format = QImage::Format_ARGB32;
-        break;
-    default:
-        Q_ASSERT(false);
-        format = QImage::Format_Invalid;
-    };
-
     QFontEngineFT::Glyph *glyph;
     if (cacheEnabled) {
         QGlyphSet *gset = loadGlyphSet(t);
@@ -1787,38 +1798,20 @@ QImage *QFontEngineFT::lockedAlphaMapForGlyph(glyph_t glyphIndex, QFixed subPixe
         glyph = loadGlyph(0, glyphIndex, subPixelPosition, neededFormat);
     }
 
-    if (glyph == 0 || glyph->data == 0 || glyph->width == 0 || glyph->height == 0) {
-        if (!cacheEnabled && glyph != &emptyGlyph)
-            delete glyph;
-        unlockFace();
-        return 0;
-    }
-
-    int pitch;
-    switch (neededFormat) {
-    case Format_Mono:
-        pitch = ((glyph->width + 31) & ~31) >> 3;
-        break;
-    case Format_A8:
-        pitch = (glyph->width + 3) & ~3;
-        break;
-    case Format_A32:
-        pitch = glyph->width * 4;
-        break;
-    default:
-        Q_ASSERT(false);
-        pitch = 0;
-    };
-
-    if (offset != 0)
+    if (offset != 0 && glyph != 0)
         *offset = QPoint(glyph->x, -glyph->y);
 
-    currentlyLockedAlphaMap = QImage(glyph->data, glyph->width, glyph->height, pitch, format);
+    currentlyLockedAlphaMap = alphaMapFromGlyphData(glyph, neededFormat);
+
     if (!cacheEnabled && glyph != &emptyGlyph) {
         currentlyLockedAlphaMap = currentlyLockedAlphaMap.copy();
         delete glyph;
     }
-    Q_ASSERT(!currentlyLockedAlphaMap.isNull());
+
+    if (currentlyLockedAlphaMap.isNull()) {
+        unlockFace();
+        return QFontEngine::lockedAlphaMapForGlyph(glyphIndex, subPixelPosition, neededFormat, t, offset);
+    }
 
     QImageData *data = currentlyLockedAlphaMap.data_ptr();
     data->is_locked = true;
@@ -1864,32 +1857,20 @@ QImage QFontEngineFT::alphaMapForGlyph(glyph_t g, QFixed subPixelPosition)
 
 QImage QFontEngineFT::alphaMapForGlyph(glyph_t g, QFixed subPixelPosition, const QTransform &t)
 {
-    Glyph *glyph = loadGlyphFor(g, subPixelPosition, antialias ? Format_A8 : Format_Mono, t);
-    if (!glyph || !glyph->data) {
-        if (!cacheEnabled && glyph != &emptyGlyph)
-            delete glyph;
-        return QFontEngine::alphaMapForGlyph(g);
-    }
+    const GlyphFormat neededFormat = antialias ? Format_A8 : Format_Mono;
 
-    const int pitch = antialias ? (glyph->width + 3) & ~3 : ((glyph->width + 31)/32) * 4;
+    Glyph *glyph = loadGlyphFor(g, subPixelPosition, neededFormat, t);
 
-    QImage img(glyph->width, glyph->height, antialias ? QImage::Format_Alpha8 : QImage::Format_Mono);
-    if (!antialias) {
-        QVector<QRgb> colors(2);
-        colors[0] = qRgba(0, 0, 0, 0);
-        colors[1] = qRgba(0, 0, 0, 255);
-        img.setColorTable(colors);
-    }
-    Q_ASSERT(img.bytesPerLine() == pitch);
-    if (glyph->width) {
-        for (int y = 0; y < glyph->height; ++y)
-            memcpy(img.scanLine(y), &glyph->data[y * pitch], pitch);
-    }
+    QImage img = alphaMapFromGlyphData(glyph, neededFormat);
+    img = img.copy();
 
     if (!cacheEnabled && glyph != &emptyGlyph)
         delete glyph;
 
-    return img;
+    if (!img.isNull())
+        return img;
+
+    return QFontEngine::alphaMapForGlyph(g);
 }
 
 QImage QFontEngineFT::alphaRGBMapForGlyph(glyph_t g, QFixed subPixelPosition, const QTransform &t)
@@ -1897,20 +1878,20 @@ QImage QFontEngineFT::alphaRGBMapForGlyph(glyph_t g, QFixed subPixelPosition, co
     if (t.type() > QTransform::TxRotate)
         return QFontEngine::alphaRGBMapForGlyph(g, subPixelPosition, t);
 
-    Glyph *glyph = loadGlyphFor(g, subPixelPosition, Format_A32, t);
-    if (!glyph || !glyph->data) {
-        if (!cacheEnabled && glyph != &emptyGlyph)
-            delete glyph;
-        return QFontEngine::alphaRGBMapForGlyph(g, subPixelPosition, t);
-    }
+    const GlyphFormat neededFormat = Format_A32;
 
-    QImage img(glyph->width, glyph->height, QImage::Format_RGB32);
-    memcpy(img.bits(), glyph->data, 4 * glyph->width * glyph->height);
+    Glyph *glyph = loadGlyphFor(g, subPixelPosition, neededFormat, t);
+
+    QImage img = alphaMapFromGlyphData(glyph, neededFormat);
+    img = img.copy();
 
     if (!cacheEnabled && glyph != &emptyGlyph)
         delete glyph;
 
-    return img;
+    if (!img.isNull())
+        return img;
+
+    return QFontEngine::alphaRGBMapForGlyph(g, subPixelPosition, t);
 }
 
 void QFontEngineFT::removeGlyphFromCache(glyph_t glyph)