FairEmail/colorpicker/src/main/java/com/flask/colorpicker/builder/PaintBuilder.java

package com.flask.colorpicker.builder;

import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader;

public class PaintBuilder {
	public static PaintHolder newPaint() {
		return new PaintHolder();
	}

	public static class PaintHolder {
		private Paint paint;

		private PaintHolder() {
			this.paint = new Paint(Paint.ANTI_ALIAS_FLAG);
		}

		public PaintHolder color(int color) {
			this.paint.setColor(color);
			return this;
		}

		public PaintHolder antiAlias(boolean flag) {
			this.paint.setAntiAlias(flag);
			return this;
		}

		public PaintHolder style(Paint.Style style) {
			this.paint.setStyle(style);
			return this;
		}

		public PaintHolder mode(PorterDuff.Mode mode) {
			this.paint.setXfermode(new PorterDuffXfermode(mode));
			return this;
		}

		public PaintHolder stroke(float width) {
			this.paint.setStrokeWidth(width);
			return this;
		}

		public PaintHolder xPerMode(PorterDuff.Mode mode) {
			this.paint.setXfermode(new PorterDuffXfermode(mode));
			return this;
		}

		public PaintHolder shader(Shader shader) {
			this.paint.setShader(shader);
			return this;
		}

		public Paint build() {
			return this.paint;
		}
	}

	public static Shader createAlphaPatternShader(int size) {
		size /= 2;
		size = Math.max(8, size * 2);
		return new BitmapShader(createAlphaBackgroundPattern(size), Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
	}

	private static Bitmap createAlphaBackgroundPattern(int size) {
		Paint alphaPatternPaint = PaintBuilder.newPaint().build();
		Bitmap bm = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);
		Canvas c = new Canvas(bm);
		int s = Math.round(size / 2f);
		for (int i = 0; i < 2; i++)
			for (int j = 0; j < 2; j++) {
				if ((i + j) % 2 == 0) alphaPatternPaint.setColor(0xffffffff);
				else alphaPatternPaint.setColor(0xffd0d0d0);
				c.drawRect(i * s, j * s, (i + 1) * s, (j + 1) * s, alphaPatternPaint);
			}
		return bm;
	}
}