Examples with PixelConverter sun.awt.image.PixelConverter used on opensource projects

Example 1 with PixelConverter

use of sun.awt.image.PixelConverter in project jdk8u_jdk by JetBrains.

the class BufferedPaints method setGradientPaint.

/************************* GradientPaint support ****************************/
/**
     * Note: This code is factored out into a separate static method
     * so that it can be shared by both the Gradient and LinearGradient
     * implementations.  LinearGradient uses this code (for the
     * two-color sRGB case only) because it can be much faster than the
     * equivalent implementation that uses fragment shaders.
     *
     * We use OpenGL's texture coordinate generator to automatically
     * apply a smooth gradient (either cyclic or acyclic) to the geometry
     * being rendered.  This technique is almost identical to the one
     * described in the comments for BufferedPaints.setTexturePaint(),
     * except the calculations take place in one dimension instead of two.
     * Instead of an anchor rectangle in the TexturePaint case, we use
     * the vector between the two GradientPaint end points in our
     * calculations.  The generator uses a single plane equation that
     * takes the (x,y) location (in device space) of the fragment being
     * rendered to calculate a (u) texture coordinate for that fragment:
     *     u = Ax + By + Cz + Dw
     *
     * The gradient renderer uses a two-pixel 1D texture where the first
     * pixel contains the first GradientPaint color, and the second pixel
     * contains the second GradientPaint color.  (Note that we use the
     * GL_CLAMP_TO_EDGE wrapping mode for acyclic gradients so that we
     * clamp the colors properly at the extremes.)  The following diagram
     * attempts to show the layout of the texture containing the two
     * GradientPaint colors (C1 and C2):
     *
     *                        +-----------------+
     *                        |   C1   |   C2   |
     *                        |        |        |
     *                        +-----------------+
     *                      u=0  .25  .5   .75  1
     *
     * We calculate our plane equation constants (A,B,D) such that u=0.25
     * corresponds to the first GradientPaint end point in user space and
     * u=0.75 corresponds to the second end point.  This is somewhat
     * non-obvious, but since the gradient colors are generated by
     * interpolating between C1 and C2, we want the pure color at the
     * end points, and we will get the pure color only when u correlates
     * to the center of a texel.  The following chart shows the expected
     * color for some sample values of u (where C' is the color halfway
     * between C1 and C2):
     *
     *       u value      acyclic (GL_CLAMP)      cyclic (GL_REPEAT)
     *       -------      ------------------      ------------------
     *        -0.25              C1                       C2
     *         0.0               C1                       C'
     *         0.25              C1                       C1
     *         0.5               C'                       C'
     *         0.75              C2                       C2
     *         1.0               C2                       C'
     *         1.25              C2                       C1
     *
     * Original inspiration for this technique came from UMD's Agile2D
     * project (GradientManager.java).
     */
private static void setGradientPaint(RenderQueue rq, AffineTransform at, Color c1, Color c2, Point2D pt1, Point2D pt2, boolean isCyclic, boolean useMask) {
    // convert gradient colors to IntArgbPre format
    PixelConverter pc = PixelConverter.ArgbPre.instance;
    int pixel1 = pc.rgbToPixel(c1.getRGB(), null);
    int pixel2 = pc.rgbToPixel(c2.getRGB(), null);
    // calculate plane equation constants
    double x = pt1.getX();
    double y = pt1.getY();
    at.translate(x, y);
    // now gradient point 1 is at the origin
    x = pt2.getX() - x;
    y = pt2.getY() - y;
    double len = Math.sqrt(x * x + y * y);
    at.rotate(x, y);
    // now gradient point 2 is on the positive x-axis
    at.scale(2 * len, 1);
    // now gradient point 2 is at (0.5, 0)
    at.translate(-0.25, 0);
    // now gradient point 1 is at (0.25, 0), point 2 is at (0.75, 0)
    double p0, p1, p3;
    try {
        at.invert();
        p0 = at.getScaleX();
        p1 = at.getShearX();
        p3 = at.getTranslateX();
    } catch (java.awt.geom.NoninvertibleTransformException e) {
        p0 = p1 = p3 = 0.0;
    }
    // assert rq.lock.isHeldByCurrentThread();
    rq.ensureCapacityAndAlignment(44, 12);
    RenderBuffer buf = rq.getBuffer();
    buf.putInt(SET_GRADIENT_PAINT);
    buf.putInt(useMask ? 1 : 0);
    buf.putInt(isCyclic ? 1 : 0);
    buf.putDouble(p0).putDouble(p1).putDouble(p3);
    buf.putInt(pixel1).putInt(pixel2);
}