add test for mac aa on fonts

Bug: skia:
Change-Id: I93b18ee84345e27eb5cf3a94feccb35391ac0e71
Reviewed-on: https://skia-review.googlesource.com/c/193661
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>

gm/mac_aa_explorer.cpp

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkSurface.h"
+
+#ifdef SK_BUILD_FOR_MAC
+
+#import <ApplicationServices/ApplicationServices.h>
+
+static CGContextRef make_cg_ctx(const SkPixmap& pm) {
+    CGBitmapInfo info;
+    CGColorSpaceRef cs;
+
+    switch (pm.colorType()) {
+        case kRGBA_8888_SkColorType:
+            info = kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast;
+            cs = CGColorSpaceCreateDeviceRGB();
+            break;
+        case kGray_8_SkColorType:
+            info = kCGImageAlphaNone;
+            cs = CGColorSpaceCreateDeviceGray();
+            break;
+        case kAlpha_8_SkColorType:
+            info = kCGImageAlphaOnly;
+            cs = nullptr;
+            break;
+        default:
+            return nullptr;
+    }
+    return CGBitmapContextCreate(pm.writable_addr(), pm.width(), pm.height(), 8, pm.rowBytes(),
+                                 cs, info);
+}
+
+static void test_mac_fonts(SkCanvas* canvas, SkScalar size) {
+    int w = 32;
+    int h = 32;
+    bool shouldAA = true;
+
+    canvas->scale(10, 10);
+    SkScalar y = 1;
+
+    for (SkColorType ct : {kRGBA_8888_SkColorType, kGray_8_SkColorType, kAlpha_8_SkColorType}) {
+        SkImageInfo ii = SkImageInfo::Make(w, h, ct, kPremul_SkAlphaType);
+        auto surf = SkSurface::MakeRaster(ii);
+        SkPixmap pm;
+        surf->peekPixels(&pm);
+        CGContextRef ctx = make_cg_ctx(pm);
+        CGContextSetAllowsFontSmoothing(ctx, true);
+        CGContextSetShouldAntialias(ctx, shouldAA);
+        CGContextSelectFont(ctx, "Helvetica", size, kCGEncodingMacRoman);
+
+        SkScalar x = 1;
+        for (bool smooth : {false, true}) {
+            surf->getCanvas()->clear(ct == kGray_8_SkColorType ? 0xFFFFFFFF : 0);
+            CGContextSetShouldSmoothFonts(ctx, smooth);
+            CGContextShowTextAtPoint(ctx, 2, 2, "A", 1);
+
+            surf->draw(canvas, x, y, nullptr);
+            x += pm.width();
+        }
+        y += pm.height();
+    }
+}
+
+class MacAAFontsGM : public skiagm::GM {
+    SkScalar fSize = 16;
+public:
+    MacAAFontsGM() {}
+    ~MacAAFontsGM() override {}
+
+protected:
+    DrawResult onDraw(SkCanvas* canvas, SkString* errorMsg) override {
+        test_mac_fonts(canvas, fSize);
+
+        return DrawResult::kOk;
+    }
+
+    SkISize onISize() override { return { 1024, 768 }; }
+
+    SkString onShortName() override { return SkString("macaatest"); }
+
+    bool onHandleKey(SkUnichar uni) override {
+        switch (uni) {
+            case 'i': fSize += 1; return true;
+            case 'k': fSize -= 1; return true;
+            default: break;
+        }
+        return false;
+    }
+};
+
+DEF_GM(return new MacAAFontsGM;)
+
+#endif
+

gn/gm.gni

@@ -221,6 +221,7 @@ gm_sources = [
   "$_gm/localmatriximageshader.cpp",
   "$_gm/localmatrixshader.cpp",
   "$_gm/lumafilter.cpp",
+  "$_gm/mac_aa_explorer.cpp",
   "$_gm/makecolorspace.cpp",
   "$_gm/makeRasterImage.cpp",
   "$_gm/mandoline.cpp",