Reland "remove SkCanvas::kIsOpaque_SaveLayerFlag"

This reverts the revert 9ff8c8c073.

Original:

    This is a performance-only hint that no one but fuzzers
    is using.  It's even explicitly filtered out in Android.

    The fuzzers have noticed they can trick us into allocating
    uninitialized memory and treating it as opaque, blending
    uninitialized pixels, etc.

    Since no one's using this, we can just kill the bit.

    Bug: skia:7566, chromium:808830

Docs-Preview: https://skia.org/?cl=105282
Change-Id: I4326c663f777aa373ff7ec9f319519da9729350d
Reviewed-on: https://skia-review.googlesource.com/105282
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>

docs/SkCanvas_Reference.bmh

@@ -1682,7 +1682,6 @@ documentation purposes, this enum is named rather than anonymous
 #Line # sets SaveLayerRec options ##
 #Code
     enum {
-        kIsOpaque_SaveLayerFlag = 1 << 0,
         kPreserveLCDText_SaveLayerFlag = 1 << 1,
         kInitWithPrevious_SaveLayerFlag = 1 << 2,
         kDontClipToLayer_Legacy_SaveLayerFlag = kDontClipToLayer_PrivateSaveLayerFlag,
@@ -1692,11 +1691,6 @@ documentation purposes, this enum is named rather than anonymous
 SaveLayerFlags provides options that may be used in any combination in SaveLayerRec,
 defining how Layer allocated by saveLayer operates.
 
-#Const kIsOpaque_SaveLayerFlag 1
-  Creates Layer without transparency. Flag is ignored if Layer Paint contains
-  Image_Filter or Color_Filter.
-##
-
 #Const kPreserveLCDText_SaveLayerFlag 2
   Creates Layer for LCD text. Flag is ignored if Layer Paint contains
   Image_Filter or Color_Filter.
@@ -1824,8 +1818,8 @@ Sets fBounds, fPaint, and fBackdrop to nullptr. Clears fSaveLayerFlags.
 
 #Example
     SkCanvas::SaveLayerRec rec1;
-    rec1.fSaveLayerFlags = SkCanvas::kIsOpaque_SaveLayerFlag;
+    rec1.fSaveLayerFlags = SkCanvas::kPreserveLCDText_SaveLayerFlag;
-    SkCanvas::SaveLayerRec rec2(nullptr, nullptr, SkCanvas::kIsOpaque_SaveLayerFlag);
+    SkCanvas::SaveLayerRec rec2(nullptr, nullptr, SkCanvas::kPreserveLCDText_SaveLayerFlag);
     SkDebugf("rec1 %c= rec2\n", rec1.fBounds == rec2.fBounds
             && rec1.fPaint == rec2.fPaint
             && rec1.fBackdrop == rec2.fBackdrop

fuzz/FuzzCanvas.cpp

@@ -1150,9 +1150,6 @@ static void fuzz_canvas(Fuzz* fuzz, SkCanvas* canvas, int depth = 9) {
                 }
                 // _DumpCanvas can't handle this.
                 // if (make_fuzz_t<bool>(fuzz)) {
-                //     saveLayerRec.fSaveLayerFlags |= SkCanvas::kIsOpaque_SaveLayerFlag;
-                // }
-                // if (make_fuzz_t<bool>(fuzz)) {
                 //     saveLayerRec.fSaveLayerFlags |= SkCanvas::kPreserveLCDText_SaveLayerFlag;
                 // }
 

include/core/SkCanvas.h

@@ -605,11 +605,6 @@ public:
         defining how layer allocated by saveLayer() operates.
     */
     enum {
-        /** Creates layer without transparency. Flag is ignored if layer SkPaint contains
-            SkImageFilter or SkColorFilter.
-        */
-        kIsOpaque_SaveLayerFlag               = 1 << 0,
-
         /** Creates layer for LCD text. Flag is ignored if layer SkPaint contains
             SkImageFilter or SkColorFilter.
         */

site/user/api/SkCanvas_Reference.md

@@ -1693,7 +1693,6 @@ depth of saved stack
 
 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
 enum {
-<a href="#SkCanvas_kIsOpaque_SaveLayerFlag">kIsOpaque SaveLayerFlag</a> = 1 << 0,
 <a href="#SkCanvas_kPreserveLCDText_SaveLayerFlag">kPreserveLCDText SaveLayerFlag</a> = 1 << 1,
 <a href="#SkCanvas_kInitWithPrevious_SaveLayerFlag">kInitWithPrevious SaveLayerFlag</a> = 1 << 2,
 <a href="#SkCanvas_kDontClipToLayer_Legacy_SaveLayerFlag">kDontClipToLayer Legacy SaveLayerFlag</a> = kDontClipToLayer_PrivateSaveLayerFlag,
@@ -1705,10 +1704,6 @@ defining how <a href="#Layer">Layer</a> allocated by <a href="#SkCanvas_saveLaye
 ### Constants
 
 <table>
-  <tr>
-    <td><a name="SkCanvas_kIsOpaque_SaveLayerFlag"> <code><strong>SkCanvas::kIsOpaque_SaveLayerFlag </strong></code> </a></td><td>1</td><td>Creates <a href="#Layer">Layer</a> without transparency. Flag is ignored if <a href="#Layer">Layer</a> <a href="SkPaint_Reference#Paint">Paint</a> contains
-<a href="undocumented#Image_Filter">Image Filter</a> or <a href="undocumented#Color_Filter">Color Filter</a>.</td>
-  </tr>
   <tr>
     <td><a name="SkCanvas_kPreserveLCDText_SaveLayerFlag"> <code><strong>SkCanvas::kPreserveLCDText_SaveLayerFlag </strong></code> </a></td><td>2</td><td>Creates <a href="#Layer">Layer</a> for LCD text. Flag is ignored if <a href="#Layer">Layer</a> <a href="SkPaint_Reference#Paint">Paint</a> contains
 <a href="undocumented#Image_Filter">Image Filter</a> or <a href="undocumented#Color_Filter">Color Filter</a>.</td>

site/user/api/catalog.htm

@@ -372,7 +372,7 @@
         "stdout": "---\\n-x-\\n---\\n"
     },
         "SkCanvas_SaveLayerRec_SaveLayerRec": {
-    "code": "void draw(SkCanvas* canvas) {\n    SkCanvas::SaveLayerRec rec1;\n    rec1.fSaveLayerFlags = SkCanvas::kIsOpaque_SaveLayerFlag;\n    SkCanvas::SaveLayerRec rec2(nullptr, nullptr, SkCanvas::kIsOpaque_SaveLayerFlag);\n    SkDebugf(\"rec1 %c= rec2\\n\", rec1.fBounds == rec2.fBounds\n            && rec1.fPaint == rec2.fPaint\n            && rec1.fBackdrop == rec2.fBackdrop\n            && rec1.fSaveLayerFlags == rec2.fSaveLayerFlags ? '=' : '!');\n}",
+    "code": "void draw(SkCanvas* canvas) {\n    SkCanvas::SaveLayerRec rec1;\n    rec1.fSaveLayerFlags = SkCanvas::kPreserveLCDText_SaveLayerFlag;\n    SkCanvas::SaveLayerRec rec2(nullptr, nullptr, SkCanvas::kPreserveLCDText_SaveLayerFlag);\n    SkDebugf(\"rec1 %c= rec2\\n\", rec1.fBounds == rec2.fBounds\n            && rec1.fPaint == rec2.fPaint\n            && rec1.fBackdrop == rec2.fBackdrop\n            && rec1.fSaveLayerFlags == rec2.fSaveLayerFlags ? '=' : '!');\n}",
     "hash": "ac7c834dce2eac6ef49c15e820e94003",
     "file": "SkCanvas_Reference",
     "name": "SkCanvas::SaveLayerRec::SaveLayerRec",
@@ -7231,4 +7231,4 @@ onclick="handleMouseClick()"
 ></canvas >
 </body>
 </html>
-    
+

src/core/SkCanvas.cpp

@@ -1036,20 +1036,18 @@ void SkCanvas::DrawDeviceWithFilter(SkBaseDevice* src, const SkImageFilter* filt
     }
 }
 
-static SkImageInfo make_layer_info(const SkImageInfo& prev, int w, int h, bool isOpaque,
+static SkImageInfo make_layer_info(const SkImageInfo& prev, int w, int h, const SkPaint* paint) {
-                                   const SkPaint* paint) {
     // need to force L32 for now if we have an image filter. Once filters support other colortypes
     // e.g. sRGB or F16, we can remove this check
     // SRGBTODO: Can we remove this check now?
     const bool hasImageFilter = paint && paint->getImageFilter();
 
-    SkAlphaType alphaType = isOpaque ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
     if ((prev.bytesPerPixel() < 4) || hasImageFilter) {
         // force to L32
-        return SkImageInfo::MakeN32(w, h, alphaType);
+        return SkImageInfo::MakeN32Premul(w, h);
     } else {
         // keep the same characteristics as the prev
-        return SkImageInfo::Make(w, h, prev.colorType(), alphaType, prev.refColorSpace());
+        return SkImageInfo::Make(w, h, prev.colorType(), kPremul_SkAlphaType, prev.refColorSpace());
     }
 }
 
@@ -1107,12 +1105,10 @@ void SkCanvas::internalSaveLayer(const SaveLayerRec& rec, SaveLayerStrategy stra
         return;
     }
 
-    bool isOpaque = SkToBool(saveLayerFlags & kIsOpaque_SaveLayerFlag);
     SkPixelGeometry geo = fProps.pixelGeometry();
     if (paint) {
         // TODO: perhaps add a query to filters so we might preserve opaqueness...
         if (paint->getImageFilter() || paint->getColorFilter()) {
-            isOpaque = false;
             geo = kUnknown_SkPixelGeometry;
         }
     }
@@ -1123,8 +1119,7 @@ void SkCanvas::internalSaveLayer(const SaveLayerRec& rec, SaveLayerStrategy stra
         return;
     }
 
-    SkImageInfo info = make_layer_info(priorDevice->imageInfo(), ir.width(), ir.height(), isOpaque,
+    SkImageInfo info = make_layer_info(priorDevice->imageInfo(), ir.width(), ir.height(), paint);
-                                       paint);
 
     sk_sp<SkBaseDevice> newDevice;
     {

src/core/SkPicturePlayback.cpp

@@ -22,7 +22,6 @@
 
 // matches old SkCanvas::SaveFlags
 enum LegacySaveFlags {
-    kHasAlphaLayer_LegacySaveFlags    = 0x04,
     kClipToLayer_LegacySaveFlags      = 0x10,
 };
 
@@ -32,9 +31,6 @@ SkCanvas::SaveLayerFlags SkCanvas::LegacySaveFlagsToSaveLayerFlags(uint32_t flag
     if (0 == (flags & kClipToLayer_LegacySaveFlags)) {
         layerFlags |= SkCanvas::kDontClipToLayer_PrivateSaveLayerFlag;
     }
-    if (0 == (flags & kHasAlphaLayer_LegacySaveFlags)) {
-        layerFlags |= kIsOpaque_SaveLayerFlag;
-    }
     return layerFlags;
 }
 

tools/debugger/SkObjectParser.cpp

@@ -349,9 +349,6 @@ SkString* SkObjectParser::RegionToString(const SkRegion& region) {
 
 SkString* SkObjectParser::SaveLayerFlagsToString(SkCanvas::SaveLayerFlags saveLayerFlags) {
     SkString* mFlags = new SkString("SkCanvas::SaveFlags: ");
-    if (saveLayerFlags & SkCanvas::kIsOpaque_SaveLayerFlag) {
-        mFlags->append("kIsOpaque_SaveLayerFlag ");
-    }
     if (saveLayerFlags & SkCanvas::kPreserveLCDText_SaveLayerFlag) {
         mFlags->append("kPreserveLCDText_SaveLayerFlag ");
     }