I'm drawing arc with canvas.drawArc(...) and use below code to add gradient to paint object but the gradient just applied on the body of arc and not the stroke. how to draw a gradient stroke?
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth((float) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, getResources().getDisplayMetrics()));
paint.setShader(new RadialGradient(getWidth()/2,getHeight()/2,mRadius/2,Color.BLUE,Color.YELLOW, Shader.TileMode.CLAMP));
canvas.drawArc(new RectF(getWidth()/2-mRadius, getHeight()/2-mRadius, getWidth()/2+mRadius, getHeight()/2+mRadius),270f,mProgressDegree,true,paint);
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On a canvas I draw figures covering each-other to get the result I want. Their transparent is 128 and on cover areas color multiple. I need whole figure in one color. How to fix it?
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Paint paint = new Paint();
paint.setColor(Color.GREEN);
Path path = new Path();
path.moveTo(margin,0);
path.lineTo(middleWidth+pieceWidth,0);
path.lineTo(middleWidth-pieceWidth,height);
path.lineTo(margin, height);
path.lineTo(margin, 0);
Path path1 = new Path();
path1.moveTo(middleWidth+pieceWidth+interval,0);
path1.lineTo(middleWidth-pieceWidth+interval,height);
path1.lineTo(width-margin,height);
path1.lineTo(width-margin,0);
path1.lineTo(middleWidth+pieceWidth+interval,0);
RectF rect = new RectF();
rect.set(0,0,middleWidth-pieceWidth,height);
RectF rect1 = new RectF();
rect1.set(middleWidth+pieceWidth,0,width,height);
paint.setStyle(Paint.Style.FILL);
paint.setColor(leftColor);
paint.setAlpha(128);
canvas.drawPath(path, paint);
paint.setColor(rightColor);
paint.setAlpha(128);
canvas.drawPath(path1, paint);
paint.setAlpha(128);
paint.setStyle(Paint.Style.FILL);
canvas.drawRoundRect(rect, corners, corners, paint);
canvas.drawRoundRect(rect1, corners, corners, paint);
}
The result is:
Result picture
I want to draw two colored circle on canvas. Everything is right but the circle isn't smooth.
This is the effect:
And this is code:
private void drawCircle(Canvas c)
{
RectF oval = new RectF(20, 20, 100, 100);
c.drawArc(oval, -90, 180, false, getPaintWithColor(R.color.background));
c.drawArc(oval, 90, 180, false, getPaintWithColor(R.color.font_grey));
}
private Paint getPaintWithColor(int colorId){
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setDither(true);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(4);
paint.setColor(getResources().getColor(colorId));
return paint;
}
paint.setFlags(Paint.ANTI_ALIAS_FLAG)
See in Can I draw with antialiasing on canvas?
I have several lines in my application. If somebody touches a line I have to highlight the line touched. I think if I could draw a transparent rectangle with light color, other than the clicked line color, then it will be highlighted properly.. So can anybody tell me how can I draw a transparent rectangle on Android canvas?
My line color is black. Please see the pic.
This will draw green 50% transparent rectangle on canvas:
Paint myPaint = new Paint();
myPaint.setStyle(Paint.Style.FILL);
myPaint.setColor(Color.rgba(0, 256, 0, 128)); // green color with 50% transparency
// c is your canvas
c.drawRect(100, 100, 200, 200, myPaint);
try this way
private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setColor(Color.RED);
mPaint.setStrokeWidth(3);
mPaint.setPathEffect(null);
canvas.drawRect(x, y, x + width, y + height, mPaint);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setColor(Color.WHITE);
mPaint.setStrokeWidth(3);
mPaint.setPathEffect(new DashPathEffect(new float[] { 5, 5 }, 5));
canvas.drawRect(x, y, x + width, y + height, mPaint);
you can use this:
Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.MAGENTA);
DashPathEffect dashPath =new DashPathEffect(new float[ ]{70,2}, 30);
paint.setPathEffect(dashPath);
paint.setStrokeWidth(80);
canvas.drawRect(30, 300 , 320, 300, paint);
Is there any way in Android to draw a filled rectangle with say a black border. My problem is that the canvas.draw() takes one paint object, and to my knowledge the paint object can't have a different color for the fill and the stroke. Is there a way around this?
Try paint.setStyle(Paint.Style.FILL) and paint.setStyle(Paint.Style.STROKE).
Paint paint = new Paint();
Rect r = new Rect(10, 10, 200, 100);
#Override
public void onDraw(Canvas canvas) {
// fill
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.MAGENTA);
canvas.drawRect(r, paint);
// border
paint.setStyle(Paint.Style.STROKE);
paint.setColor(Color.BLACK);
canvas.drawRect(r, paint);
}
If you are drawing multiple views then you could also use two paints, one for the stroke and one for the fill. That way you don't have to keep resetting them.
Paint fillPaint = new Paint();
Paint strokePaint = new Paint();
RectF r = new RectF(30, 30, 1000, 500);
void initPaints() {
// fill
fillPaint.setStyle(Paint.Style.FILL);
fillPaint.setColor(Color.YELLOW);
// stroke
strokePaint.setStyle(Paint.Style.STROKE);
strokePaint.setColor(Color.BLACK);
strokePaint.setStrokeWidth(10);
}
#Override
protected void onDraw(Canvas canvas) {
// First rectangle
canvas.drawRect(r, fillPaint); // fill
canvas.drawRect(r, strokePaint); // stroke
canvas.translate(0, 600);
// Second rectangle
int cornerRadius = 50;
canvas.drawRoundRect(r, cornerRadius, cornerRadius, fillPaint); // fill
canvas.drawRoundRect(r, cornerRadius, cornerRadius, strokePaint); // stroke
}
You draw a rectangle with the color of the border and the size of the rectangle plus the border, you change the color of the paint and draw again the rectangle with the normal size.
I'm overriding Android's ImageView in order to make the corners of my image transparent. I can accomplish that clipping the canvas in my onDraw(Canvas canvas):
#Override
protected void onDraw(Canvas canvas) {
Path clipPath = new Path();
int w = this.getWidth();
int h = this.getHeight();
clipPath.addRoundRect(new RectF(0,0,w,h), 10.0f, 10.0f, Path.Direction.CW);
canvas.clipPath(clipPath);
super.onDraw(canvas);
}
Unfortunately, it's not possible to antialias this round rectangle, and the result are ugly corners like this:
I know I can clear parts of my canvas with antialiasing using Paint and PorterDuff.Mode.CLEAR, what I don't know is to specify the round corners as the region to be erased. I'm looking for something like this:
#Override
protected void onDraw(Canvas canvas) {
//superclass will draw the bitmap accordingly
super.onDraw(canvas);
final Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
//this will erase a round rectangle, I need the exact inverse
canvas.drawRoundRect(rect, rx, ry, paint);
}
Is there any way to "erase" not the round rectangle, but it's inverse, ie, the round corners? And what if I just want to erase one of the corners?
Draw using a BitmapShader with a transparent color for your Paint object.
If you just want to erase one of the corners, try drawing it as a Path instead of a RoundRect.
protected void onDraw(Canvas canvas) {
BitmapShader bitmapShader = new BitmapShader(<original drawable>, TileMode.CLAMP, TileMode.CLAMP);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(0xFF000000);
paint.setShader(bitmapShader);
canvas.drawRoundRect(rect, rx, ry, paint);
}