/*
* 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 "SampleCode.h"
#include "SkView.h"
#include "SkCanvas.h"
#include "SkGradientShader.h"
#include "SkGraphics.h"
#include "SkPath.h"
#include "SkRegion.h"
#include "SkShader.h"
#include "SkUtils.h"
#include "SkColorPriv.h"
#include "SkColorFilter.h"
#include "SkTime.h"
#include "SkTypeface.h"
class PathClipView : public SampleView {
public:
SkRect fOval;
SkPoint fCenter;
PathClipView() : fOval(SkRect::MakeWH(200, 50)), fCenter(SkPoint::Make(250, 250)) {}
protected:
bool onQuery(SkEvent* evt) override {
if (SampleCode::TitleQ(*evt)) {
SampleCode::TitleR(evt, "PathClip");
return true;
}
return this->INHERITED::onQuery(evt);
}
void onDrawContent(SkCanvas* canvas) override {
const SkRect oval = fOval.makeOffset(fCenter.fX - fOval.centerX(),
fCenter.fY - fOval.centerY());
SkPaint p;
p.setAntiAlias(true);
p.setStyle(SkPaint::kStroke_Style);
canvas->drawOval(oval, p);
const SkRect r = SkRect::MakeLTRB(200, 200, 300, 300);
canvas->clipRect(r);
p.setStyle(SkPaint::kFill_Style);
p.setColor(SK_ColorRED);
canvas->drawRect(r, p);
p.setColor(0x800000FF);
canvas->drawOval(oval, p);
}
SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned) override {
return new Click(this);
}
bool onClick(Click* click) override {
fCenter.set(click->fCurr.fX, click->fCurr.fY);
return false;
}
private:
typedef SampleView INHERITED;
};
DEF_SAMPLE( return new PathClipView; )
//////////////////////////////////////////////////////////////////////////////
static int clip_line(const SkRect& bounds, SkPoint p0, SkPoint p1, SkPoint edges[]) {
SkPoint* edgesStart = edges;
if (p0.fY == p1.fY) {
return 0;
}
if (p0.fY > p1.fY) {
SkTSwap(p0, p1);
}
// now we're monotonic in Y: p0 <= p1
if (p1.fY <= bounds.top() || p0.fY >= bounds.bottom()) {
return 0;
}
double dxdy = (double)(p1.fX - p0.fX) / (p1.fY - p0.fY);
if (p0.fY < bounds.top()) {
p0.fX = SkDoubleToScalar(p0.fX + dxdy * (bounds.top() - p0.fY));
p0.fY = bounds.top();
}
if (p1.fY > bounds.bottom()) {
p1.fX = SkDoubleToScalar(p1.fX + dxdy * (bounds.bottom() - p1.fY));
p1.fY = bounds.bottom();
}
// Now p0...p1 is strictly inside bounds vertically, so we just need to clip horizontally
if (p0.fX > p1.fX) {
SkTSwap(p0, p1);
}
// now we're left-to-right: p0 .. p1
if (p1.fX <= bounds.left()) { // entirely to the left
p0.fX = p1.fX = bounds.left();
*edges++ = p0;
*edges++ = p1;
return 2;
}
if (p0.fX >= bounds.right()) { // entirely to the right
p0.fX = p1.fX = bounds.right();
*edges++ = p0;
*edges++ = p1;
return 2;
}
if (p0.fX < bounds.left()) {
float y = SkDoubleToScalar(p0.fY + (bounds.left() - p0.fX) / dxdy);
*edges++ = SkPoint::Make(bounds.left(), p0.fY);
*edges++ = SkPoint::Make(bounds.left(), y);
p0.set(bounds.left(), y);
}
if (p1.fX > bounds.right()) {
float y = SkDoubleToScalar(p0.fY + (bounds.right() - p0.fX) / dxdy);
*edges++ = p0;
*edges++ = SkPoint::Make(bounds.right(), y);
*edges++ = SkPoint::Make(bounds.right(), p1.fY);
} else {
*edges++ = p0;
*edges++ = p1;
}
return SkToInt(edges - edgesStart);
}
static void draw_clipped_line(SkCanvas* canvas, const SkRect& bounds,
SkPoint p0, SkPoint p1, const SkPaint& paint) {
SkPoint verts[6];
int count = clip_line(bounds, p0, p1, verts);
SkPath path;
path.addPoly(verts, count, false);
canvas->drawPath(path, paint);
}
// Demonstrate edge-clipping that is used in the scan converter
//
class EdgeClipView : public SampleView {
enum {
N = 3
};
public:
SkPoint fPoly[N];
SkRect fClip;
SkColor fEdgeColor[N];
EdgeClipView() : fClip(SkRect::MakeLTRB(150, 150, 550, 450)) {
fPoly[0].set(300, 40);
fPoly[1].set(550, 250);
fPoly[2].set(40, 450);
fEdgeColor[0] = 0xFFFF0000;
fEdgeColor[1] = 0xFF00FF00;
fEdgeColor[2] = 0xFF0000FF;
}
protected:
bool onQuery(SkEvent* evt) override {
if (SampleCode::TitleQ(*evt)) {
SampleCode::TitleR(evt, "EdgeClip");
return true;
}
return this->INHERITED::onQuery(evt);
}
static SkScalar snap(SkScalar x) {
return SkScalarRoundToScalar(x * 0.5f) * 2;
}
static SkPoint snap(const SkPoint& pt) {
return SkPoint::Make(snap(pt.x()), snap(pt.y()));
}
static void snap(SkPoint dst[], const SkPoint src[], int count) {
for (int i = 0; i < count; ++i) {
dst[i] = snap(src[i]);
}
}
void onDrawContent(SkCanvas* canvas) override {
SkPath path;
path.addPoly(fPoly, N, true);
// Draw the full triangle, stroked and filled
SkPaint p;
p.setAntiAlias(true);
p.setColor(0xFFE0E0E0);
canvas->drawPath(path, p);
p.setStyle(SkPaint::kStroke_Style);
p.setStrokeWidth(2);
for (int i = 0; i < N; ++i) {
const int j = (i + 1) % N;
p.setColor(fEdgeColor[i]);
p.setAlpha(0x88);
canvas->drawLine(fPoly[i], fPoly[j], p);
}
p.setStyle(SkPaint::kFill_Style);
// Draw the clip itself
p.setColor(0xFF8888CC);
canvas->drawRect(fClip, p);
// Draw the filled triangle through the clip
p.setColor(0xFF88CC88);
canvas->save();
canvas->clipRect(fClip);
canvas->drawPath(path, p);
canvas->restore();
p.setStyle(SkPaint::kStroke_Style);
p.setStrokeWidth(6);
// Draw each of the "Edges" that survived the clipping
// We use a layer, so we can PLUS the different edge-colors, showing where two edges
// canceled each other out.
canvas->saveLayer(nullptr, nullptr);
p.setBlendMode(SkBlendMode::kPlus);
for (int i = 0; i < N; ++i) {
const int j = (i + 1) % N;
p.setColor(fEdgeColor[i]);
draw_clipped_line(canvas, fClip, fPoly[i], fPoly[j], p);
}
canvas->restore();
}
class MyClick : public Click {
public:
MyClick(SkView* view) : Click(view) {}
virtual void handleMove() = 0;
};
class VertClick : public MyClick {
SkPoint* fPt;
public:
VertClick(SkView* view, SkPoint* pt) : MyClick(view), fPt(pt) {}
void handleMove() override { *fPt = snap(fCurr); }
};
class DragRectClick : public MyClick {
SkRect* fRect;
public:
DragRectClick(SkView* view, SkRect* rect) : MyClick(view), fRect(rect) {}
void handleMove() override { fRect->offset(fCurr.x() - fPrev.x(), fCurr.y() - fPrev.y()); }
};
class DragPolyClick : public MyClick {
SkPoint fSrc[100];
SkPoint* fPoly;
int fCount;
public:
DragPolyClick(SkView* view, SkPoint poly[], int count)
: MyClick(view), fPoly(poly), fCount(count)
{
SkASSERT((size_t)count <= SK_ARRAY_COUNT(fSrc));
memcpy(fSrc, poly, count * sizeof(SkPoint));
}
void handleMove() override {
const SkScalar dx = fCurr.x() - fOrig.x();
const SkScalar dy = fCurr.y() - fOrig.y();
for (int i = 0; i < fCount; ++i) {
fPoly[i].set(snap(fSrc[i].x() + dx), snap(fSrc[i].y() + dy));
}
}
};
class DoNothingClick : public MyClick {
public:
DoNothingClick(SkView* view) : MyClick(view) {}
void handleMove() override {}
};
static bool hit_test(const SkPoint& pt, SkScalar x, SkScalar y) {
const SkScalar rad = 8;
const SkScalar dx = pt.x() - x;
const SkScalar dy = pt.y() - y;
return dx*dx + dy*dy <= rad*rad;
}
SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned) override {
for (int i = 0; i < N; ++i) {
if (hit_test(fPoly[i], x, y)) {
return new VertClick(this, &fPoly[i]);
}
}
SkPath path;
path.addPoly(fPoly, N, true);
if (path.contains(x, y)) {
return new DragPolyClick(this, fPoly, N);
}
if (fClip.intersects(SkRect::MakeLTRB(x - 1, y - 1, x + 1, y + 1))) {
return new DragRectClick(this, &fClip);
}
return new DoNothingClick(this);
}
bool onClick(Click* click) override {
((MyClick*)click)->handleMove();
return false;
}
private:
typedef SampleView INHERITED;
};
DEF_SAMPLE( return new EdgeClipView; )