Develop Reference

Draw Text Over Bitmap

I'm trying to put text over map marker but it always appears under it.
First I convert drawable to bitmap and then draw text on it. drawable to bitmap conversion works fine, I only have a problem with text overlay.
I have already tried these:
Adding text to a bitmap in memory in Android
https://stackoverflow.com/a/7328777/3423468
https://stackoverflow.com/a/8831182/3423468
and many more with no luck.
This is my current method:
Bitmap drawableToBitmap(Drawable drawable)
{
var bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
var canvas = new Canvas(bitmap);
if (shouldDrawText)
{
Paint paint = new Paint();
paint.setColor(Color.WHITE);
paint.setStrokeWidth(40);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER)); // Text Overlapping Pattern
//canvas.drawBitmap(bitmap, 0, 0, paint);
canvas.drawText("Testing...", 10, 10, paint);
}
drawable.SetBounds(0, 0, canvas.Width, canvas.Height);
drawable.Draw(canvas);
return bitmap;
}
Any ideas what I'm doing wrong?

paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER)); // Text Overlapping Pattern
Here you use SRC_OVER, which means the source will be over the DST will be under. The DST is the new pixels to be drawn.
You should use DST_OVER to draw the new pixels on top of the old pixels.
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OVER)); // Text Overlapping Pattern
See here an overview of how porterduff works

How to draw multiple bitmap using paint?

I am trying to draw multiple bitmap using this code.
Paint paint = new Paint();
Path path = new Path(); // path of crop
for (int i = 0; i < Crop.points.size(); i++) {
path.lineTo(Crop.points.get(i).x, Crop.points.get(i).y);
canvas.drawPath(path, paint);
bitmap1= highlightImage(bitmap1); //bitmap1 drawn completely
canvas.drawBitmap(bitmap1, 0, 0, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));// select inside part of crop
canvas.drawBitmap(bitmap2, 0, 0, paint);// draw crop part
highlightImage is a method for blurring a bitmap. This canvas first draw bitmap1 that is blurred and then draw bitmap2.
The problem is, when I use only this code:
bitmap1= highlightImage(bitmap1);
canvas.drawBitmap(bitmap1, 0, 0, paint);
the bitmap1 is blurred and drawn correctly, but when I use this
bitmap1= highlightImage(bitmap1);
canvas.drawBitmap(bitmap1, 0, 0, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap2, 0, 0, paint);
the bitmap1 is drawn but without the blur effect. What's the problem?
the first image is the image of blur bitmap
the second one is for the time that two bit map is drawn. you can see that is transparent without blur effect.
[first ][1]
[second ][2]
[what I want][3]

Draw text with a shape mask?

I am drawing text on a canvas. I would like to draw a solid circle of color over the text, and only have the circle be painted where it intersects the text. Example:
and what I want to do:
I'm not sure if this is possible, my draw code is simply:
public void onDraw(Canvas canvas) {
canvas.drawText("Hello", x, y, paint);
paint.setColor(orange);
canvas.drawOval(...);
}
I suppose I would need to apply some masking, but not sure how to get started.

follow this tutorial from a googler...
android-shaders-filters
BitmapShader may help you

You can use PorterDuffXfermode in Android to achieve this.
If you use below code it will work fine:
Bitmap original = Bitmap.createBitmap(canvas.getWidth(), canvas.getHeight(),
Bitmap.Config.ARGB_8888); // Created from Canvas
Bitmap mask =
Bitmap.createBitmap(getContext().getResources(),R.drawable.mask_image);
Bitmap result = Bitmap.createBitmap(mask.getWidth(), mask.getHeight(),
Config.ARGB_8888);
Canvas tempCanvas = new Canvas(result);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
tempCanvas.drawBitmap(original, 0, 0, null);
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
tempCanvas.drawBitmap(mask, 0, 0, paint);
paint.setXfermode(null);
canvas.drawBitmap(result, 0, 0, new Paint());
What does PorterDuff.Mode mean in android graphics.What does it do?

How to mask only certain parts of a bitmap in Android

I want to be able to use the following image to mask other bitmap. So basically, I'm trying to get the mask image and replace it's black content with another bitmap. Like this for example:
I'm able to use this mask and create a round version of the original bitmap, but that does not retain that orange border around it. Any thoughts on how I can accomplish this effect? Thanks.
The code that I am using (that only creates a round image) is the following:
private static Bitmap applyMask(ImageView imageView, Bitmap mainImage) {
Canvas canvas = new Canvas();
Bitmap result result = Bitmap.createBitmap(50, 50, Bitmap.Config.ARGB_8888);
canvas.setBitmap(result);
Paint paint = new Paint();
// resize image fills the whole canvas
canvas.drawBitmap(mainImage, null, new Rect(0, 0, 50, 50), paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
canvas.drawBitmap(sMaskImage, 0, 0, paint);
paint.setXfermode(null);
return result;
}

I use below code snipped to set masked images, this sample "bm" is my bitmap and "mMaskSource" is the resource id of mask object position in my drawable folder.
Bitmap mask = BitmapFactory.decodeResource(getResources(), mMaskSource);
Bitmap result = Bitmap.createBitmap(mask.getWidth(), mask.getHeight(),
Config.ARGB_8888);
Canvas mCanvas = new Canvas(result);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
bm = Bitmap.createScaledBitmap(bm, mask.getWidth(), mask.getHeight(),
true);
mCanvas.drawBitmap(bm, 0, 0, null);
mCanvas.drawBitmap(mask, 0, 0, paint);
paint.setXfermode(null);
And finally you can use "result" bitmap object however you wish.

Android Mask two Bitmap clear border

I'm using the mask a bitmap with another. The operation succeeds well, unfortunately the result of masking seen a slight black border, as you can see in the image:
How do I remove this border? in the source image is not there.
I'll post the code I'm using:
public Bitmap mask(Bitmap source) {
Bitmap targetBitmap = Bitmap.createBitmap(getWidth(),getHeight(),
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(targetBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
paint.setAntiAlias(true);
paint.setDither(true);
canvas.drawBitmap(source, 0, 0, null);
canvas.drawBitmap(getMask(), 0, 0, paint);
paint.setXfermode(null);
return targetBitmap;
}
where getMask () returns the Bitmap that represents the figure of the Puzzle.
I hope to receive your help, thank you all
Sorry for my english :-)
UPDATE:
the black border is what I point out in this picture:
UPDATE:
place the sequence of transformation. The third image would be identical to the first but without color. The problem is the black edge of the puzzle.
I hope to be more clear:

The way I draw images with mask is kind of the other way around from what you do.
public Bitmap mask(Bitmap source) {
Bitmap targetBitmap = Bitmap.createBitmap(getWidth(),getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(targetBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
// paint.setAntiAlias(true); // you've already set this in the constructor
paint.setDither(true);
canvas.drawBitmap(getMask(), 0, 0, null);
canvas.drawBitmap(source, 0, 0, paint);
// paint.setXfermode(null); // no need for this
return targetBitmap;
}
Note that PorterDuff.Mode is set to SRC_IN (not DST_in) and that the mask is drawn first and then the image on top of that mask. With this approach you can also draw the previous source as the base mask, add the new (puzzle) mask and then draw the final source/image on top of that with SRC_IN paint to add new puzzle pieces each time.
If that doesn't solve the black border, check that your mask doesn't have feathered (transparent) edges that might be causing these problems.
Also, ANTI_ALIAS_FLAG doesn't do anything on textures. If you want smoothly scaled textures use paint.setFilterBitmap(true);