skia2/gm/dashing.cpp

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/*
* Copyright 2012 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 "SkDashPathEffect.h"
static void drawline(SkCanvas* canvas, int on, int off, const SkPaint& paint,
SkScalar finalX = SkIntToScalar(600)) {
SkPaint p(paint);
const SkScalar intervals[] = {
SkIntToScalar(on),
SkIntToScalar(off),
};
p.setPathEffect(new SkDashPathEffect(intervals, 2, 0))->unref();
canvas->drawLine(0, 0, finalX, 0, p);
}
// earlier bug stopped us from drawing very long single-segment dashes, because
// SkPathMeasure was skipping very small delta-T values (nearlyzero). This is
// now fixes, so this giant dash should appear.
static void show_giant_dash(SkCanvas* canvas) {
SkPaint paint;
drawline(canvas, 1, 1, paint, SkIntToScalar(20 * 1000));
}
class DashingGM : public skiagm::GM {
public:
DashingGM() {}
protected:
SkString onShortName() {
return SkString("dashing");
}
SkISize onISize() { return skiagm::make_isize(640, 300); }
virtual void onDraw(SkCanvas* canvas) {
static const struct {
int fOnInterval;
int fOffInterval;
} gData[] = {
{ 1, 1 },
{ 4, 1 },
};
SkPaint paint;
paint.setStyle(SkPaint::kStroke_Style);
canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
canvas->translate(0, SK_ScalarHalf);
for (int width = 0; width <= 2; ++width) {
for (size_t data = 0; data < SK_ARRAY_COUNT(gData); ++data) {
for (int aa = 0; aa <= 1; ++aa) {
int w = width * width * width;
paint.setAntiAlias(SkToBool(aa));
paint.setStrokeWidth(SkIntToScalar(w));
int scale = w ? w : 1;
drawline(canvas, gData[data].fOnInterval * scale,
gData[data].fOffInterval * scale,
paint);
canvas->translate(0, SkIntToScalar(20));
}
}
}
show_giant_dash(canvas);
}
};
///////////////////////////////////////////////////////////////////////////////
static void make_unit_star(SkPath* path, int n) {
SkScalar rad = -SK_ScalarPI / 2;
const SkScalar drad = (n >> 1) * SK_ScalarPI * 2 / n;
path->moveTo(0, -SK_Scalar1);
for (int i = 1; i < n; i++) {
rad += drad;
SkScalar cosV, sinV = SkScalarSinCos(rad, &cosV);
path->lineTo(cosV, sinV);
}
path->close();
}
static void make_path_line(SkPath* path, const SkRect& bounds) {
path->moveTo(bounds.left(), bounds.top());
path->lineTo(bounds.right(), bounds.bottom());
}
static void make_path_rect(SkPath* path, const SkRect& bounds) {
path->addRect(bounds);
}
static void make_path_oval(SkPath* path, const SkRect& bounds) {
path->addOval(bounds);
}
static void make_path_star(SkPath* path, const SkRect& bounds) {
make_unit_star(path, 5);
SkMatrix matrix;
matrix.setRectToRect(path->getBounds(), bounds, SkMatrix::kCenter_ScaleToFit);
path->transform(matrix);
}
class Dashing2GM : public skiagm::GM {
public:
Dashing2GM() {}
protected:
SkString onShortName() {
return SkString("dashing2");
}
SkISize onISize() { return skiagm::make_isize(640, 480); }
virtual void onDraw(SkCanvas* canvas) {
static const int gIntervals[] = {
3, // 3 dashes: each count [0] followed by intervals [1..count]
2, 10, 10,
4, 20, 5, 5, 5,
2, 2, 2
};
void (*gProc[])(SkPath*, const SkRect&) = {
make_path_line, make_path_rect, make_path_oval, make_path_star,
};
SkPaint paint;
paint.setAntiAlias(true);
paint.setStyle(SkPaint::kStroke_Style);
paint.setStrokeWidth(SkIntToScalar(6));
SkRect bounds = SkRect::MakeWH(SkIntToScalar(120), SkIntToScalar(120));
bounds.offset(SkIntToScalar(20), SkIntToScalar(20));
SkScalar dx = bounds.width() * 4 / 3;
SkScalar dy = bounds.height() * 4 / 3;
const int* intervals = &gIntervals[1];
for (int y = 0; y < gIntervals[0]; ++y) {
SkScalar vals[SK_ARRAY_COUNT(gIntervals)]; // more than enough
int count = *intervals++;
for (int i = 0; i < count; ++i) {
vals[i] = SkIntToScalar(*intervals++);
}
SkScalar phase = vals[0] / 2;
paint.setPathEffect(new SkDashPathEffect(vals, count, phase))->unref();
for (size_t x = 0; x < SK_ARRAY_COUNT(gProc); ++x) {
SkPath path;
SkRect r = bounds;
r.offset(x * dx, y * dy);
gProc[x](&path, r);
canvas->drawPath(path, paint);
}
}
}
};
//////////////////////////////////////////////////////////////////////////////
static skiagm::GM* F0(void*) { return new DashingGM; }
static skiagm::GM* F1(void*) { return new Dashing2GM; }
static skiagm::GMRegistry gR0(F0);
static skiagm::GMRegistry gR1(F1);