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      1 /*
      2  * Copyright 2013 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "gm.h"
      9 #include "SkCanvas.h"
     10 #include "SkPath.h"
     11 
     12 namespace skiagm {
     13 
     14 // This GM tests a grab-bag of non-closed paths. All these paths look like
     15 // closed rects, but they don't call path.close(). Depending on the stroke
     16 // settings these slightly different paths give widely different results.
     17 class NonClosedPathsGM: public GM {
     18 public:
     19     NonClosedPathsGM() {}
     20 
     21     enum ClosureType {
     22         TotallyNonClosed,  // The last point doesn't coincide with the first one in the contour.
     23                            // The path looks not closed at all.
     24 
     25         FakeCloseCorner,   // The last point coincides with the first one at a corner.
     26                            // The path looks closed, but final rendering has 2 ends with cap.
     27 
     28         FakeCloseMiddle,   // The last point coincides with the first one in the middle of a line.
     29                            // The path looks closed, and the final rendering looks closed too.
     30 
     31         kClosureTypeCount
     32     };
     33 
     34 protected:
     35 
     36     SkString onShortName() override {
     37         return SkString("nonclosedpaths");
     38     }
     39 
     40     // 12 * 18 + 3 cases, every case is 100 * 100 pixels.
     41     SkISize onISize() override {
     42         return SkISize::Make(1220, 1920);
     43     }
     44 
     45     // Use rect-like geometry for non-closed path, for right angles make it
     46     // easier to show the visual difference of lineCap and lineJoin.
     47     static void MakePath(SkPath* path, ClosureType type) {
     48         if (FakeCloseMiddle == type) {
     49             path->moveTo(30, 50);
     50             path->lineTo(30, 30);
     51         } else {
     52             path->moveTo(30, 30);
     53         }
     54         path->lineTo(70, 30);
     55         path->lineTo(70, 70);
     56         path->lineTo(30, 70);
     57         path->lineTo(30, 50);
     58         if (FakeCloseCorner == type) {
     59             path->lineTo(30, 30);
     60         }
     61     }
     62 
     63     // Set the location for the current test on the canvas
     64     static void SetLocation(SkCanvas* canvas, int counter, int lineNum) {
     65         SkScalar x = SK_Scalar1 * 100 * (counter % lineNum) + 10 + SK_Scalar1 / 4;
     66         SkScalar y = SK_Scalar1 * 100 * (counter / lineNum) + 10 + 3 * SK_Scalar1 / 4;
     67         canvas->translate(x, y);
     68     }
     69 
     70     void onDraw(SkCanvas* canvas) override {
     71         // Stroke widths are:
     72         // 0(may use hairline rendering), 10(common case for stroke-style)
     73         // 40 and 50(>= geometry width/height, make the contour filled in fact)
     74         constexpr int kStrokeWidth[] = {0, 10, 40, 50};
     75         int numWidths = SK_ARRAY_COUNT(kStrokeWidth);
     76 
     77         constexpr SkPaint::Style kStyle[] = {
     78             SkPaint::kStroke_Style, SkPaint::kStrokeAndFill_Style
     79         };
     80 
     81         constexpr SkPaint::Cap kCap[] = {
     82             SkPaint::kButt_Cap, SkPaint::kRound_Cap, SkPaint::kSquare_Cap
     83         };
     84 
     85         constexpr SkPaint::Join kJoin[] = {
     86             SkPaint::kMiter_Join, SkPaint::kRound_Join, SkPaint::kBevel_Join
     87         };
     88 
     89         constexpr ClosureType kType[] = {
     90             TotallyNonClosed, FakeCloseCorner, FakeCloseMiddle
     91         };
     92 
     93         int counter = 0;
     94         SkPaint paint;
     95         paint.setAntiAlias(true);
     96 
     97         // For stroke style painter and fill-and-stroke style painter
     98         for (size_t type = 0; type < kClosureTypeCount; ++type) {
     99             for (size_t style = 0; style < SK_ARRAY_COUNT(kStyle); ++style) {
    100                 for (size_t cap = 0; cap < SK_ARRAY_COUNT(kCap); ++cap) {
    101                     for (size_t join = 0; join < SK_ARRAY_COUNT(kJoin); ++join) {
    102                         for (int width = 0; width < numWidths; ++width) {
    103                             canvas->save();
    104                             SetLocation(canvas, counter, SkPaint::kJoinCount * numWidths);
    105 
    106                             SkPath path;
    107                             MakePath(&path, kType[type]);
    108 
    109                             paint.setStyle(kStyle[style]);
    110                             paint.setStrokeCap(kCap[cap]);
    111                             paint.setStrokeJoin(kJoin[join]);
    112                             paint.setStrokeWidth(SkIntToScalar(kStrokeWidth[width]));
    113 
    114                             canvas->drawPath(path, paint);
    115                             canvas->restore();
    116                             ++counter;
    117                         }
    118                     }
    119                 }
    120             }
    121         }
    122 
    123         // For fill style painter
    124         paint.setStyle(SkPaint::kFill_Style);
    125         for (size_t type = 0; type < kClosureTypeCount; ++type) {
    126             canvas->save();
    127             SetLocation(canvas, counter, SkPaint::kJoinCount * numWidths);
    128 
    129             SkPath path;
    130             MakePath(&path, kType[type]);
    131 
    132             canvas->drawPath(path, paint);
    133             canvas->restore();
    134             ++counter;
    135         }
    136     }
    137 
    138 private:
    139     typedef GM INHERITED;
    140 };
    141 
    142 //////////////////////////////////////////////////////////////////////////////
    143 
    144 DEF_GM(return new NonClosedPathsGM;)
    145 
    146 }
    147