在画布上画一颗心
在画布上画一颗心
提问于 2014-04-01 01:57:00
我想在画布上画一个心形。我找到了不同的数学方程，但我无法将它们转换为可以在onDraw方法中实现的代码。我希望这里有一颗类似于这个形状的心：
我所追求的形状方程:
回答 2
Stack Overflow用户
回答已采纳
发布于 2014-04-01 03:28:59
Android绘图api不提供绘制任意方程曲线的工具。如果您愿意离开为心脏找到的特定功能形式，您可以使用三次Bezier曲线绘制心脏(没有颜色影响)，这些曲线得到api的支持。您将创建一个Path，然后使用它的cubicTo方法添加曲线段。然后，您将使用Path来呈现Canvas#drawPath。
要使用立方Bezier曲线来获得心脏形状，请看一看这个例子 (碰巧在JavaScript中，但是这个想法应该很容易移植到Android)。
我不知道什么是最好的方法是创建一个颜色梯度的心脏形状。我的建议是使用Bezier曲线定义心脏的内部和外部边界，并将其设置为Paint的剪辑区域。然后，您可以使用该Paint进行梯度填充，以限制绘制梯度的位置。
Stack Overflow用户
发布于 2020-04-15 10:32:04
public class HeartShape extends FrameLayout {
private Paint paint;
public HeartShape(@NonNull Context context) {
super(context);
init();
}
private void init() {
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);
paint.setStyle(Style.STROKE);
setWillNotDraw(false);
}
public HeartShape(@NonNull Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public HeartShape(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
public HeartShape(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
init();
}
@Override
protected void onDraw(Canvas canvas) {
Path path = createHeartPath(canvas.getClipBounds().right,canvas.getClipBounds().bottom);
canvas.drawPath(path,paint);
super.onDraw(canvas);
}
private Path createHeartPath(int width, int height) {
Path path = new Path();
path.moveTo(0,height/3f);
path.lineTo(width,height/3f);
path.moveTo(width/2f,0f);
path.lineTo(width/2f,height);
float pX = width/2f;
float pY = (height/100f)*33.33f;
float x1 = (width/100f)*50;
float y1 = (height/100f)*5;
float x2 = (width/100f)*90;
float y2 = (height/100f)*10;
float x3 = (width/100f)*90;
float y3 = (height/100f)*33.33f;
path.moveTo(pX,pY);
path.cubicTo(x1, y1, x2, y2, x3, y3);
path.moveTo(x3,pY);
x1 = (width/100f)*90;
y1 = (height/100f)*55f;
x2 = (width/100f)*65;
y2 = (height/100f)*60f;
x3 = (width/100f)*50;
y3 = (height/100f)*90f;
path.cubicTo(x1, y1, x2, y2, x3, y3);
// path.lineTo(pX,pY);
x1 = (width/100f)*50;
y1 = (height/100f)*5;
x2 = (width/100f)*10;
y2 = (height/100f)*10;
x3 = (width/100f)*10;
y3 = (height/100f)*33.33f;
path.moveTo(pX,pY);
path.cubicTo(x1, y1, x2, y2, x3, y3);
path.moveTo(x3,pY);
x1 = (width/100f)*10;
y1 = (height/100f)*55f;
x2 = (width/100f)*35f;
y2 = (height/100f)*60f;
x3 = (width/100f)*50f;
y3 = (height/100f)*90f;
path.cubicTo(x1, y1, x2, y2, x3, y3);
//path.lineTo(pX,pY);
path.moveTo(x3,y3);
path.close();
return path;
}
}Output
删除绘图行代码并设置paint.setStyle(Style.FILL);
private Path createHeartPath(int width, int height) {
Path path = new Path();
//path.moveTo(0,height/3f);
//path.lineTo(width,height/3f);
//path.moveTo(width/2f,0f);
//path.lineTo(width/2f,height);
float pX = width/2f;
float pY = (height/100f)*33.33f;
float x1 = (width/100f)*50;
float y1 = (height/100f)*5;
float x2 = (width/100f)*90;
float y2 = (height/100f)*10;
float x3 = (width/100f)*90;
float y3 = (height/100f)*33.33f;
path.moveTo(pX,pY);
path.cubicTo(x1, y1, x2, y2, x3, y3);
path.moveTo(x3,pY);
x1 = (width/100f)*90;
y1 = (height/100f)*55f;
x2 = (width/100f)*65;
y2 = (height/100f)*60f;
x3 = (width/100f)*50;
y3 = (height/100f)*90f;
path.cubicTo(x1, y1, x2, y2, x3, y3);
path.lineTo(pX,pY);
x1 = (width/100f)*50;
y1 = (height/100f)*5;
x2 = (width/100f)*10;
y2 = (height/100f)*10;
x3 = (width/100f)*10;
y3 = (height/100f)*33.33f;
path.moveTo(pX,pY);
path.cubicTo(x1, y1, x2, y2, x3, y3);
path.moveTo(x3,pY);
x1 = (width/100f)*10;
y1 = (height/100f)*55f;
x2 = (width/100f)*35f;
y2 = (height/100f)*60f;
x3 = (width/100f)*50f;
y3 = (height/100f)*90f;
path.cubicTo(x1, y1, x2, y2, x3, y3);
path.lineTo(pX,pY);
path.moveTo(x3,y3);
path.close();
return path;
}
我们可以修改createHeartPath()方法的逻辑/绘图物理，得到更好的输出，提出新的建议和改变。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/22775442
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