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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     virtual SkString onShortName() SK_OVERRIDE {
     36         return SkString("nonclosedpaths");
     37     }
     38 
     39     // 12 * 18 + 3 cases, every case is 100 * 100 pixels.
     40     virtual SkISize onISize() SK_OVERRIDE {
     41         return SkISize::Make(1220, 1920);
     42     }
     43 
     44     // Use rect-like geometry for non-closed path, for right angles make it
     45     // easier to show the visual difference of lineCap and lineJoin.
     46     static void MakePath(SkPath* path, ClosureType type) {
     47         if (FakeCloseMiddle == type) {
     48             path->moveTo(30, 50);
     49             path->lineTo(30, 30);
     50         } else {
     51             path->moveTo(30, 30);
     52         }
     53         path->lineTo(70, 30);
     54         path->lineTo(70, 70);
     55         path->lineTo(30, 70);
     56         path->lineTo(30, 50);
     57         if (FakeCloseCorner == type) {
     58             path->lineTo(30, 30);
     59         }
     60     }
     61 
     62     // Set the location for the current test on the canvas
     63     static void SetLocation(SkCanvas* canvas, int counter, int lineNum) {
     64         SkScalar x = SK_Scalar1 * 100 * (counter % lineNum) + 10 + SK_Scalar1 / 4;
     65         SkScalar y = SK_Scalar1 * 100 * (counter / lineNum) + 10 + 3 * SK_Scalar1 / 4;
     66         canvas->translate(x, y);
     67     }
     68 
     69     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
     70         // Stroke widths are:
     71         // 0(may use hairline rendering), 10(common case for stroke-style)
     72         // 40 and 50(>= geometry width/height, make the contour filled in fact)
     73         static const int kStrokeWidth[] = {0, 10, 40, 50};
     74         size_t numWidths = SK_ARRAY_COUNT(kStrokeWidth);
     75 
     76         static const SkPaint::Style kStyle[] = {
     77             SkPaint::kStroke_Style, SkPaint::kStrokeAndFill_Style
     78         };
     79 
     80         static const SkPaint::Cap kCap[] = {
     81             SkPaint::kButt_Cap, SkPaint::kRound_Cap, SkPaint::kSquare_Cap
     82         };
     83 
     84         static const SkPaint::Join kJoin[] = {
     85             SkPaint::kMiter_Join, SkPaint::kRound_Join, SkPaint::kBevel_Join
     86         };
     87 
     88         static const ClosureType kType[] = {
     89             TotallyNonClosed, FakeCloseCorner, FakeCloseMiddle
     90         };
     91 
     92         int counter = 0;
     93         SkPaint paint;
     94         paint.setAntiAlias(true);
     95 
     96         // For stroke style painter and fill-and-stroke style painter
     97         for (size_t type = 0; type < kClosureTypeCount; ++type) {
     98             for (size_t style = 0; style < SK_ARRAY_COUNT(kStyle); ++style) {
     99                 for (size_t cap = 0; cap < SK_ARRAY_COUNT(kCap); ++cap) {
    100                     for (size_t join = 0; join < SK_ARRAY_COUNT(kJoin); ++join) {
    101                         for (size_t width = 0; width < numWidths; ++width) {
    102                             canvas->save();
    103                             SetLocation(canvas, counter, SkPaint::kJoinCount * numWidths);
    104 
    105                             SkPath path;
    106                             MakePath(&path, kType[type]);
    107 
    108                             paint.setStyle(kStyle[style]);
    109                             paint.setStrokeCap(kCap[cap]);
    110                             paint.setStrokeJoin(kJoin[join]);
    111                             paint.setStrokeWidth(SkIntToScalar(kStrokeWidth[width]));
    112 
    113                             canvas->drawPath(path, paint);
    114                             canvas->restore();
    115                             ++counter;
    116                         }
    117                     }
    118                 }
    119             }
    120         }
    121 
    122         // For fill style painter
    123         paint.setStyle(SkPaint::kFill_Style);
    124         for (size_t type = 0; type < kClosureTypeCount; ++type) {
    125             canvas->save();
    126             SetLocation(canvas, counter, SkPaint::kJoinCount * numWidths);
    127 
    128             SkPath path;
    129             MakePath(&path, kType[type]);
    130 
    131             canvas->drawPath(path, paint);
    132             canvas->restore();
    133             ++counter;
    134         }
    135     }
    136 
    137 private:
    138     typedef GM INHERITED;
    139 };
    140 
    141 //////////////////////////////////////////////////////////////////////////////
    142 
    143 DEF_GM(return new NonClosedPathsGM;)
    144 
    145 }
    146