How can we tile a vector image?

Question

With the support library now fully supporting vector images, I'm trying to switch to vector images as much as I can in my app. An issue I'm running into is that it seems impossible to repeat them.

With bitmap images the following xml could be used:

<bitmap
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:src="@drawable/repeat_me"
    android:tileMode="repeat"
    />

This does not work, as vector images can not be used in bitmaps: https://code.google.com/p/android/issues/detail?id=187566

Is there any other way to tile/repeat vector images?

Answer 1

This is the java version of Nick Butcher solution:

import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;

public class TileDrawable extends Drawable {

    private final Paint paint;

    public TileDrawable(Drawable drawable, Shader.TileMode tileMode) {
        paint = new Paint();
        paint.setShader(new BitmapShader(getBitmap(drawable), tileMode, tileMode));
    }

    @Override
    public void draw(@NonNull Canvas canvas) {
        canvas.drawPaint(paint);
    }

    @Override
    public void setAlpha(int alpha) {
        paint.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(@Nullable ColorFilter colorFilter) {
        paint.setColorFilter(colorFilter);
    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSLUCENT;
    }

    private Bitmap getBitmap(Drawable drawable) {
        if (drawable instanceof BitmapDrawable)
            return ((BitmapDrawable) drawable).getBitmap();
        Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
        drawable.draw(canvas);
        return bitmap;
    }

}

You can use this drawable class in code with vector patterns:

view.setBackground(new TileDrawable(getContext().getDrawable(R.drawable.pattern), Shader.TileMode.REPEAT));

Answer 2

Thanks to @pskink I made a drawable that tiles another drawable: https://gist.github.com/9ffbdf01478e36194f8f

This has to be set in code, it can not be used from XML:

public class TilingDrawable extends android.support.v7.graphics.drawable.DrawableWrapper {

    private boolean callbackEnabled = true;

    public TilingDrawable(Drawable drawable) {
        super(drawable);
    }

    @Override
    public void draw(Canvas canvas) {
        callbackEnabled = false;
        Rect bounds = getBounds();
        Drawable wrappedDrawable = getWrappedDrawable();

        int width = wrappedDrawable.getIntrinsicWidth();
        int height = wrappedDrawable.getIntrinsicHeight();
        for (int x = bounds.left; x < bounds.right + width - 1; x+= width) {
            for (int y = bounds.top; y < bounds.bottom + height - 1; y += height) {
                wrappedDrawable.setBounds(x, y, x + width, y + height);
                wrappedDrawable.draw(canvas);
            }
        }
        callbackEnabled = true;
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
    }

    /**
     * {@inheritDoc}
     */
    public void invalidateDrawable(Drawable who) {
        if (callbackEnabled) {
            super.invalidateDrawable(who);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void scheduleDrawable(Drawable who, Runnable what, long when) {
        if (callbackEnabled) {
            super.scheduleDrawable(who, what, when);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void unscheduleDrawable(Drawable who, Runnable what) {
        if (callbackEnabled) {
            super.unscheduleDrawable(who, what);
        }
    }
}