moz-skia/gm/linepaths.cpp

182 строки
6.9 KiB
C++
Исходник Обычный вид История

Modifying SkPath to store all verbs provided by the user, and to give correct results for all stroke and fill modes even on the various types of degenerate paths. The goals of this patch include: 1. Have Skia store all of the verbs implied by path construction methods, even if those define degenerate paths. The SVG implementation in WebKit, which is backed by Skia, needs to know about all elements of the path, even degenerate ones, for the correct drawing of markers and line caps. For example, in SVG you should be able to draw a scatter plot by specifying a marker for vertices and then giving a sequence of moveTo commands. Skia will not store the moveTos, requiring a different storage mechanism. 2. Assuming 1, maintain the current Skia behavior. That is, make Skia robust to degenerate paths. 3. Fix an existing bug in Skia where a degenerate moveTo-lineTo pair spits out warnings from rasterization and produces incorrect results in inverse-fill renderings. 4. Adds extensive testing for degenerate paths and path rendering in general. To meet these goals, the patch I am proposing will result in minor additional storage for degenerate paths (a few bytes per degenerate path, only if the user defines such paths). There is also some additional overhead in the iteration code, with the path now cleaned to remove degenerate segments as part of the iteration process. I suspect this will also fix issues with computing normal vectors to degenerate segments. Benchmarking suggests that this change may result in slightly (< 1%) slower path drawing due to the checks for degeneracy. This overhead could be removed (in fact, a significant speedup could occur) if the results of iterating to clean up the path were cached. This would cost memory, of course, and quite a bit of it. BUG=398 TEST=tests/PathTest.cpp gm/cubicpaths.cpp gm/degeneratesegments.cpp gm/movepaths.cpp gm/linepaths.cpp gm/quadpaths.cpp Review URL: http://codereview.appspot.com/5482051 git-svn-id: http://skia.googlecode.com/svn/trunk@2901 2bbb7eff-a529-9590-31e7-b0007b416f81
2011-12-20 19:14:18 +04:00
/*
* Copyright 2011 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 "SkCanvas.h"
#include "SkPaint.h"
#include "SkRandom.h"
namespace skiagm {
class LinePathsGM : public GM {
public:
LinePathsGM() {}
protected:
SkString onShortName() {
return SkString("linepaths");
}
SkISize onISize() { return make_isize(1800, 1110); }
void drawPath(SkPath& path,SkCanvas* canvas,SkColor color,
const SkRect& clip,SkPaint::Cap cap,
SkPaint::Style style, SkPath::FillType fill,
SkScalar strokeWidth) {
path.setFillType(fill);
SkPaint paint;
paint.setStrokeCap(cap);
paint.setStrokeWidth(strokeWidth);
paint.setColor(color);
paint.setStyle(style);
canvas->save();
canvas->clipRect(clip);
canvas->drawPath(path, paint);
canvas->restore();
}
virtual void onDraw(SkCanvas* canvas) {
struct FillAndName {
SkPath::FillType fFill;
const char* fName;
};
static const FillAndName gFills[] = {
{SkPath::kWinding_FillType, "Winding"},
{SkPath::kEvenOdd_FillType, "Even / Odd"},
{SkPath::kInverseWinding_FillType, "Inverse Winding"},
{SkPath::kInverseEvenOdd_FillType, "Inverse Even / Odd"},
};
struct StyleAndName {
SkPaint::Style fStyle;
const char* fName;
};
static const StyleAndName gStyles[] = {
{SkPaint::kFill_Style, "Fill"},
{SkPaint::kStroke_Style, "Stroke"},
{SkPaint::kStrokeAndFill_Style, "Stroke And Fill"},
};
struct CapAndName {
SkPaint::Cap fCap;
const char* fName;
};
static const CapAndName gCaps[] = {
{SkPaint::kButt_Cap, "Butt"},
{SkPaint::kRound_Cap, "Round"},
{SkPaint::kSquare_Cap, "Square"},
};
struct PathAndName {
SkPath fPath;
const char* fName;
};
PathAndName gPaths[4];
gPaths[0].fPath.moveTo(50*SK_Scalar1, 15*SK_Scalar1);
gPaths[0].fPath.lineTo(50*SK_Scalar1, 15*SK_Scalar1);
gPaths[0].fName = "moveTo-zeroline";
gPaths[1].fPath.moveTo(50*SK_Scalar1, 15*SK_Scalar1);
gPaths[1].fPath.lineTo(50*SK_Scalar1, 15*SK_Scalar1);
gPaths[1].fPath.close();
gPaths[1].fName = "moveTo-zeroline-close";
gPaths[2].fPath.moveTo(30*SK_Scalar1, 15*SK_Scalar1);
gPaths[2].fPath.lineTo(70*SK_Scalar1, 15*SK_Scalar1);
gPaths[2].fName = "moveTo-line";
gPaths[3].fPath.moveTo(30*SK_Scalar1, 15*SK_Scalar1);
gPaths[3].fPath.lineTo(70*SK_Scalar1, 15*SK_Scalar1);
gPaths[3].fPath.close();
gPaths[3].fName = "moveTo-line-close";
SkPaint titlePaint;
titlePaint.setColor(SK_ColorBLACK);
titlePaint.setAntiAlias(true);
titlePaint.setLCDRenderText(true);
titlePaint.setTextSize(15 * SK_Scalar1);
const char title[] = "Line Paths Drawn Into Rectangle Clips With "
"Indicated Style, Fill and Linecaps, "
"with random stroke widths";
canvas->drawText(title, strlen(title),
20 * SK_Scalar1,
20 * SK_Scalar1,
titlePaint);
SkRandom rand;
SkRect rect = SkRect::MakeWH(100*SK_Scalar1, 30*SK_Scalar1);
canvas->save();
canvas->translate(10 * SK_Scalar1, 30 * SK_Scalar1);
canvas->save();
for (size_t path = 0; path < SK_ARRAY_COUNT(gPaths); ++path) {
if (0 < path) {
canvas->translate(0, (rect.height() + 60 * SK_Scalar1) * 3);
}
canvas->save();
for (size_t cap = 0; cap < SK_ARRAY_COUNT(gCaps); ++cap) {
if (0 < cap) {
canvas->translate((rect.width() + 40 * SK_Scalar1) * 4, 0);
}
canvas->save();
for (size_t style = 0; style < SK_ARRAY_COUNT(gStyles); ++style) {
if (0 < style) {
canvas->translate(0, rect.height() + 60 * SK_Scalar1);
}
canvas->save();
for (size_t fill = 0; fill < SK_ARRAY_COUNT(gFills); ++fill) {
if (0 < fill) {
canvas->translate(rect.width() + 40 * SK_Scalar1, 0);
}
SkColor color = 0xff007000;
this->drawPath(gPaths[path].fPath, canvas, color, rect,
gCaps[cap].fCap, gStyles[style].fStyle,
gFills[fill].fFill, SK_Scalar1*10);
SkPaint rectPaint;
rectPaint.setColor(SK_ColorBLACK);
rectPaint.setStyle(SkPaint::kStroke_Style);
rectPaint.setStrokeWidth(-1);
rectPaint.setAntiAlias(true);
canvas->drawRect(rect, rectPaint);
SkPaint labelPaint;
labelPaint.setColor(color);
labelPaint.setAntiAlias(true);
labelPaint.setLCDRenderText(true);
labelPaint.setTextSize(10 * SK_Scalar1);
canvas->drawText(gStyles[style].fName,
strlen(gStyles[style].fName),
0, rect.height() + 12 * SK_Scalar1,
labelPaint);
canvas->drawText(gFills[fill].fName,
strlen(gFills[fill].fName),
0, rect.height() + 24 * SK_Scalar1,
labelPaint);
canvas->drawText(gCaps[cap].fName,
strlen(gCaps[cap].fName),
0, rect.height() + 36 * SK_Scalar1,
labelPaint);
canvas->drawText(gPaths[path].fName,
strlen(gPaths[path].fName),
0, rect.height() + 48 * SK_Scalar1,
labelPaint);
}
canvas->restore();
}
canvas->restore();
}
canvas->restore();
}
canvas->restore();
canvas->restore();
}
private:
typedef GM INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
static GM* MyFactory(void*) { return new LinePathsGM; }
static GMRegistry reg(MyFactory);
}