Add 'P' to SampleApp to cycle through pixel geometries.

samplecode/SampleApp.cpp

Index: samplecode/SampleApp.cpp
diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 3149711d86b30e88784715a4862c7c526b714896..36e89498f58e98af419a8ce0b942a5c26ff0fa27 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -468,6 +468,20 @@ static HintingState gHintingStates[] = {
     {SkPaint::kFull_Hinting, "Full", "Hf " },
 };
 
+struct PixelGeometryState {
+    SkPixelGeometry pixelGeometry;
+    const char* name;
+    const char* label;
+};
+static PixelGeometryState gPixelGeometryStates[] = {
+    {SkPixelGeometry::kUnknown_SkPixelGeometry, "Mixed", nullptr },
+    {SkPixelGeometry::kUnknown_SkPixelGeometry, "Flat",  "{Flat} "  },

[reed1, 2016/03/31 11:04:13]

I presume Flat means ... unknown?

[bungeman-skia, 2016/03/31 14:15:27]

Right here I'm not stating that the created surface should have some unknown
pixel geometry or that the eventual display's pixel geometry is unknown, but
stating that I'm creating a surface where the pixel geometry is explicitly flat.
Using the term "Flat" here in the UI is stating that the surface's pixel
geometry is flat, it most assuredly is not "unknown". Indeed, the "Mixed"
actually means something more like unknown, since the pixelGeometry in the above
PixelGeometryState is just a dummy, it isn't used (the legacy default is what is
used).
 
From the user's perspective, it's kUnknown that's misnamed. SkPixelGeometry is
used to specify the pixel geometry of the SkSurface, it doesn't need to reflect
the user's knowledge of where the SkSurface will eventually end up. In other
words, by specifying the SkPixelGeometry on a surface the user is definitively
configuring the surface, in which case stating 'I don't know what you should be'
isn't very clear. 'kFlat_SkPixelGeometry' or even 'kNone_SkPixelGeometry' would
be better names.  If some user doesn't know the pixel geometry of the eventual
display device then of course they should explicitly state 'flat' as opposed to
just 'unknown'.

The naming of this is somewhat a matter of perspective. The use of 'kUnknown'
reflects what the names would be if one were to query a device for its pixel
geometry. (Though in this case 'kUnknown' would probably better be called
'kOther'.) Since in Skia these enum names are only ever used to create a surface
(not query a device) I believe they should have the perspective of telling the
surface what its pixel geometry is.

+    {SkPixelGeometry::kRGB_H_SkPixelGeometry,   "RGB H", "{RGB H} " },
+    {SkPixelGeometry::kBGR_H_SkPixelGeometry,   "BGR H", "{BGR H} " },
+    {SkPixelGeometry::kRGB_V_SkPixelGeometry,   "RGB_V", "{RGB V} " },
+    {SkPixelGeometry::kBGR_V_SkPixelGeometry,   "BGR_V", "{BGR V} " },
+};
+
 struct FilterQualityState {
     SkFilterQuality fQuality;
     const char*     fName;
@@ -852,7 +866,7 @@ SampleWindow::SampleWindow(void* hwnd, int argc, char** argv, DeviceManager* dev
         fDeviceType = kGPU_DeviceType;
     }
 #endif
-        
+
 #if DEFAULT_TO_GPU
     fDeviceType = kGPU_DeviceType;
 #endif
@@ -875,6 +889,7 @@ SampleWindow::SampleWindow(void* hwnd, int argc, char** argv, DeviceManager* dev
     fAAState = SkOSMenu::kMixedState;
     fSubpixelState = SkOSMenu::kMixedState;
     fHintingState = 0;
+    fPixelGeometryIndex = 0;
     fFilterQualityIndex = 0;
     fFlipAxis = 0;
 
@@ -935,6 +950,16 @@ SampleWindow::SampleWindow(void* hwnd, int argc, char** argv, DeviceManager* dev
                                   nullptr);
     fAppMenu->assignKeyEquivalentToItem(itemID, 'h');
 
+    itemID = fAppMenu->appendList("Pixel Geometry", "Pixel Geometry", sinkID, fPixelGeometryIndex,
+                                  gPixelGeometryStates[0].name,
+                                  gPixelGeometryStates[1].name,
+                                  gPixelGeometryStates[2].name,
+                                  gPixelGeometryStates[3].name,
+                                  gPixelGeometryStates[4].name,
+                                  gPixelGeometryStates[5].name,
+                                  nullptr);
+    fAppMenu->assignKeyEquivalentToItem(itemID, 'P');
+
     itemID =fAppMenu->appendList("Tiling", "Tiling", sinkID, fTilingMode,
                                  gTilingInfo[kNo_Tiling].label,
                                  gTilingInfo[kAbs_128x128_Tiling].label,
@@ -1611,6 +1636,10 @@ bool SampleWindow::onEvent(const SkEvent& evt) {
         this->updateTitle();
         return true;
     }
+    if (SkOSMenu::FindListIndex(evt, "Pixel Geometry", &fPixelGeometryIndex)) {
+        this->setPixelGeometry(fPixelGeometryIndex);
+        return true;
+    }
     if (SkOSMenu::FindListIndex(evt, "Tiling", &fTilingMode)) {
         if (SampleView::IsSampleView(curr_view(this))) {
             ((SampleView*)curr_view(this))->onTileSizeChanged(this->tileSize());
@@ -1792,13 +1821,11 @@ bool SampleWindow::onHandleChar(SkUnichar uni) {
 void SampleWindow::setDeviceType(DeviceType type) {
     if (type == fDeviceType)
         return;
-    
+
     fDevManager->tearDownBackend(this);
-    
     fDeviceType = type;
-    
     fDevManager->setUpBackend(this, fMSAASampleCount);
-    
+
     this->updateTitle();
     this->inval(nullptr);
 }
@@ -1807,9 +1834,8 @@ void SampleWindow::setDeviceColorType(SkColorType ct, SkColorProfileType pt) {
     this->setColorType(ct, pt);
 
     fDevManager->tearDownBackend(this);
-    
     fDevManager->setUpBackend(this, fMSAASampleCount);
-    
+
     this->updateTitle();
     this->inval(nullptr);
 }
@@ -1845,6 +1871,23 @@ void SampleWindow::toggleDistanceFieldFonts() {
     this->inval(nullptr);
 }
 
+void SampleWindow::setPixelGeometry(int pixelGeometryIndex) {
+    // reset backend
+    fDevManager->tearDownBackend(this);
+    fDevManager->setUpBackend(this, fMSAASampleCount);
+
+    const SkSurfaceProps& oldProps = this->getSurfaceProps();
+    SkSurfaceProps newProps(oldProps.flags(), SkSurfaceProps::kLegacyFontHost_InitType);
+    if (pixelGeometryIndex > 0) {
+        newProps = SkSurfaceProps(oldProps.flags(),
+                                  gPixelGeometryStates[pixelGeometryIndex].pixelGeometry);
+    }
+    this->setSurfaceProps(newProps);
+
+    this->updateTitle();
+    this->inval(nullptr);
+}
+
 #include "SkDumpCanvas.h"
 
 bool SampleWindow::onHandleKey(SkKey key) {
@@ -2071,6 +2114,7 @@ void SampleWindow::updateTitle() {
     title.prepend(fFlipAxis & kFlipAxis_X ? "X " : nullptr);
     title.prepend(fFlipAxis & kFlipAxis_Y ? "Y " : nullptr);
     title.prepend(gHintingStates[fHintingState].label);
+    title.prepend(gPixelGeometryStates[fPixelGeometryIndex].label);
 
     if (fOffset.fX || fOffset.fY) {
         title.prependf("(%.2f, %.2f) ", SkScalarToFloat(fOffset.fX), SkScalarToFloat(fOffset.fY));