Refactor QTextureGlyphCache

Separate getting the glyph coordinates from actually making and
populating the cache. Calling populate() and fillInPendingGlyphs()
immediately after should be equivalent to the old code, except it might
have fewer reallocations of the texture since you will only create it
one per set of glyphs.

This mainly enables populating the GL glyph cache outside a GL context
and then actually drawing into it later, when the context has actually
been established.

Reviewed-by: Kim

1 files changed, 36 insertions, 11 deletions

diff --git a/src/gui/painting/qtextureglyphcache.cpp b/src/gui/painting/qtextureglyphcache.cpp
index 631a9cf8fa..29cd82b328 100644
--- a/src/gui/painting/qtextureglyphcache.cpp
+++ b/src/gui/painting/qtextureglyphcache.cpp
@@ -126,8 +126,9 @@ void QTextureGlyphCache::populate(QFontEngine *fontEngine, int numGlyphs, const
         return;
 
     rowHeight += margin * 2 + paddingDoubled;
-    if (isNull())
-        createCache(QT_DEFAULT_TEXTURE_GLYPH_CACHE_WIDTH, qt_next_power_of_two(rowHeight));
+
+    if (m_w == 0)
+        m_w = QT_DEFAULT_TEXTURE_GLYPH_CACHE_WIDTH;
 
     // now actually use the coords and paint the wanted glyps into cache.
     QHash<glyph_t, Coord>::iterator iter = listItemCoordinates.begin();
@@ -142,26 +143,50 @@ void QTextureGlyphCache::populate(QFontEngine *fontEngine, int numGlyphs, const
             m_cy += m_currentRowHeight + paddingDoubled;
             m_currentRowHeight = 0; // New row
         }
-        if (m_cy + c.h > m_h) {
-            int new_height = m_h*2;
-            while (new_height < m_cy + c.h)
-                new_height *= 2;
-            // if no room in the current texture - realloc a larger texture
-            resizeTextureData(m_w, new_height);
-            m_h = new_height;
-        }
 
         c.x = m_cx;
         c.y = m_cy;
 
-        fillTexture(c, iter.key());
         coords.insert(iter.key(), c);
+        m_pendingGlyphs.insert(iter.key(), c);
 
         m_cx += c.w + paddingDoubled;
         ++iter;
     }
+}
+
+void QTextureGlyphCache::fillInPendingGlyphs()
+{
+    if (m_pendingGlyphs.isEmpty())
+        return;
+
+    int requiredHeight = 0;
+    {
+        QHash<glyph_t, Coord>::iterator iter = m_pendingGlyphs.begin();
+        while (iter != m_pendingGlyphs.end()) {
+            Coord c = iter.value();
+            requiredHeight = qMax(requiredHeight, c.y + c.h);
+            ++iter;
+        }
+    }
+
+    if (requiredHeight > m_h) {
+        if (isNull())
+            createCache(m_w, qt_next_power_of_two(requiredHeight));
+        else
+            resizeCache(m_w, qt_next_power_of_two(requiredHeight));
+    }
 
+    {
+        QHash<glyph_t, Coord>::iterator iter = m_pendingGlyphs.begin();
+        while (iter != m_pendingGlyphs.end()) {
+            fillTexture(iter.value(), iter.key());
+
+            ++iter;
+        }
+    }
 
+    m_pendingGlyphs.clear();
 }
 
 QImage QTextureGlyphCache::textureMapForGlyph(glyph_t g) const