ColorPicker.java 文件源码

private Bitmap createColorWheelBitmap(int width, int height) {

        Bitmap bitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);

        int colorCount = 12;
        int colorAngleStep = 360 / 12;
        int colors[] = new int[colorCount + 1];
        float hsv[] = new float[] { 0f, 1f, 1f };
        for (int i = 0; i < colors.length; i++) {
            hsv[0] = (i * colorAngleStep + 180) % 360;
            colors[i] = Color.HSVToColor(hsv);
        }
        colors[colorCount] = colors[0];

        SweepGradient sweepGradient = new SweepGradient(width / 2, height / 2, colors, null);
        RadialGradient radialGradient = new RadialGradient(width / 2, height / 2, colorWheelRadius, 0xFFFFFFFF, 0x00FFFFFF, TileMode.CLAMP);
        ComposeShader composeShader = new ComposeShader(sweepGradient, radialGradient, PorterDuff.Mode.SRC_OVER);

        colorWheelPaint.setShader(composeShader);

        Canvas canvas = new Canvas(bitmap);
        canvas.drawCircle(width / 2, height / 2, colorWheelRadius, colorWheelPaint);

        return bitmap;

    }