CODEWITHSUNDEEP
androidcanvasbitmap
Wai Yan Hein
Wai Yan Hein

Reputation: 14771

How to draw an image on top a bitmap and combine as one bitmap in Android Java

I am developing an Android application using Java. I am doing some image manipulating in my application. First of all, I like to save I have no knowledge about image processing. But, I am trying to get into it. What I would like to do now is draw a simple image on a bitmap and save it as one bitmap.

I am loading an image from asset folder as a bitmap like this.

Bitmap rectBitmap = BitmapFactory.decodeStream(istr);

Let's say the photo is a just simple rectangle like this.

enter image description here

Then I would like to draw a bitmap (triangle shape) using coordinates point. The image would be some this.

enter image description here

My imagination of code would be like this.

rectBitmap.drawOnTop(coorPointOneValues, coorPointTwoValues, coorPointThreeValues);

Coordinate point values would be x and y value since I am working on the 2D coordinate system.

Then I would like to save the image something like this after drawing traingle

rectBitmap = rectBitmap.saveBitmap();

How can I do it? The scenario mentioned is a possible way that I can think of. If it is not possible, what would be the other way around?

Upvotes: 0

Views: 646

Answers (1)

L. Swifter
L. Swifter

Reputation: 3237

You can do it like this.

1, read or create your bitmap:

Bitmap rectBitmap = BitmapFactory.decodeStream(istr);
Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);

2, create a canvas on the bitmap:

Canvas canvas = new Canvas(bitmap);

3, draw something:

canvas.drawColor(Color.RED)   
canvas.drawRect / canvas.drawLine / canvas.drawArc ...
//for triangle shape you can use drawPath

4, save the bitmap:

bitmap.compress(CompressFormat format, int quality, OutputStream stream)

Upvotes: 2

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