CODEWITHSUNDEEP
androidandroid-canvasandroid-drawable
Lana
Lana

Reputation: 1201

Drawable image on a canvas

How can I get an image to a canvas in order to draw on that image?

Upvotes: 118

Views: 200349

Answers (7)

Mahozad
Mahozad

Reputation: 24732

To preserve the aspect ratio of my vector drawable I did this (in Kotlin):

val drawable = resources.getDrawable(R.drawable.my_vector, null)
val aspectRatio = drawable.intrinsicWidth.toFloat() / drawable.intrinsicHeight
val desiredWidthInPx = 100
val derivedHeightInPx = (desiredWidthInPx / aspectRatio).toInt()
drawable.setBounds(0, 0, desiredWidthInPx, derivedHeightInPx)
drawable.draw(canvas)

Upvotes: 3

Gábor
Gábor

Reputation: 10274

The good way to draw a Drawable on a canvas is not decoding it yourself but leaving it to the system to do so:

Drawable d = getResources().getDrawable(R.drawable.foobar, null);
d.setBounds(left, top, right, bottom);
d.draw(canvas);

This will work with all kinds of drawables, not only bitmaps. And it also means that you can re-use that same drawable again if only the size changes.

Upvotes: 214

34m0
34m0

Reputation: 5955

Drawable d = ContextCompat.getDrawable(context, R.drawable.***)
d.setBounds(left, top, right, bottom);
d.draw(canvas);

Upvotes: 16

AzizAhmad
AzizAhmad

Reputation: 647

also you can use this way. it will change your big drawble fit to your canvas:

Resources res = getResources();
Bitmap bitmap = BitmapFactory.decodeResource(res, yourDrawable);
yourCanvas.drawBitmap(bitmap, 0, 0, yourPaint);

Upvotes: 16

user1140237
user1140237

Reputation: 5045

package com.android.jigsawtest;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class SurafaceClass extends SurfaceView implements
        SurfaceHolder.Callback {
    Bitmap mBitmap;
Paint paint =new Paint();
    public SurafaceClass(Context context) {
        super(context);
        mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        // TODO Auto-generated method stub

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub

    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawColor(Color.BLACK);
        canvas.drawBitmap(mBitmap, 0, 0, paint);

    }

}

Upvotes: 2

Konstantin Burov
Konstantin Burov

Reputation: 69238

You need to load your image as bitmap:

 Resources res = getResources();
 Bitmap bitmap = BitmapFactory.decodeResource(res, R.drawable.your_image);

Then make the bitmap mutable and create a canvas over it:

Canvas canvas = new Canvas(bitmap.copy(Bitmap.Config.ARGB_8888, true));

You then can draw on the canvas.

Upvotes: 41

Rohit Mandiwal
Rohit Mandiwal

Reputation: 10462

try this

Bitmap mBitmap = Bitmap.createScaledBitmap(Bitmap src, int dstWidth, int dstHeight, boolean filter);

protected void onDraw(Canvas canvas) {
            canvas.drawColor(0xFFAAAAAA);
            canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);

        }

Upvotes: 8

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