use triangle filter for odd dimensions in mip-levels

gm/showmiplevels.cpp

 /*
  * Copyright 2016 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 "Resources.h"
 #include "SkBitmapScaler.h"
 #include "SkGradientShader.h"
 #include "SkTypeface.h"
 #include "SkImageDecoder.h"
 #include "SkStream.h"
 #include "SkPaint.h"
 #include "SkMipMap.h"
 #include "Resources.h"
 #include "sk_tool_utils.h"
 
+#define SHOW_MIP_COLOR  0xFF000000
+
 static SkBitmap make_bitmap(int w, int h) {
     SkBitmap bm;
     bm.allocN32Pixels(w, h);
     SkCanvas canvas(bm);
     canvas.clear(0xFFFFFFFF);
     SkPaint paint;
     paint.setStyle(SkPaint::kStroke_Style);
     paint.setStrokeWidth(w / 16.0f);
+    paint.setColor(SHOW_MIP_COLOR);
     canvas.drawCircle(w/2.0f, h/2.0f, w/3.0f, paint);
     return bm;
 }
 
 static SkBitmap make_bitmap2(int w, int h) {
     SkBitmap bm;
     bm.allocN32Pixels(w, h);
     SkCanvas canvas(bm);
     canvas.clear(0xFFFFFFFF);
     SkPaint paint;
+    paint.setColor(SHOW_MIP_COLOR);
     paint.setStyle(SkPaint::kStroke_Style);
 
     SkScalar inset = 2;
     SkRect r = SkRect::MakeIWH(w, h).makeInset(0.5f, 0.5f);
     while (r.width() > 4) {
         canvas.drawRect(r, paint);
         r.inset(inset, inset);
         inset += 1;
     }
     return bm;
 }
 
 #include "SkNx.h"
 static SkBitmap make_bitmap3(int w, int h) {
     SkBitmap bm;
     bm.allocN32Pixels(w, h);
     SkCanvas canvas(bm);
     canvas.clear(0xFFFFFFFF);
     SkPaint paint;
     paint.setStyle(SkPaint::kStroke_Style);
     paint.setStrokeWidth(2.1f);
+    paint.setColor(SHOW_MIP_COLOR);
 
     SkScalar s = SkIntToScalar(w);
     Sk4f p(s, -s, -s, s);
     Sk4f d(5);
     while (p.kth<1>() < s) {
         canvas.drawLine(p.kth<0>(),p.kth<1>(), p.kth<2>(), p.kth<3>(), paint);
         p = p + d;
     }
     return bm;
 }
@@ skipping 145 matching lines @@
 
 /**
  *  Show mip levels that were built, for all supported colortypes
  */
 class ShowMipLevels2 : public skiagm::GM {
     const int fW, fH;
     SkBitmap  fBM[4];
 
 public:
     ShowMipLevels2(int w, int h) : fW(w), fH(h) {
-        fBM[0] = sk_tool_utils::create_checkerboard_bitmap(w, h, SK_ColorBLACK, SK_ColorWHITE, 2);
+        fBM[0] = sk_tool_utils::create_checkerboard_bitmap(w, h, SHOW_MIP_COLOR, SK_ColorWHITE, 2);
         fBM[1] = make_bitmap(w, h);
         fBM[2] = make_bitmap2(w, h);
         fBM[3] = make_bitmap3(w, h);
     }
 
 protected:
 
     SkString onShortName() override {
         SkString str;
         str.printf("showmiplevels2_%dx%d", fW, fH);
@@ skipping 68 matching lines @@
         }
     }
     
 private:
     typedef skiagm::GM INHERITED;
 };
 DEF_GM( return new ShowMipLevels2(255, 255); )
 DEF_GM( return new ShowMipLevels2(256, 255); )
 DEF_GM( return new ShowMipLevels2(255, 256); )
 DEF_GM( return new ShowMipLevels2(256, 256); )