/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.java2d.pipe;

import java.awt.Color;

import java.awt.GradientPaint;

import java.awt.LinearGradientPaint;

import java.awt.MultipleGradientPaint;

import java.awt.MultipleGradientPaint.ColorSpaceType;

import java.awt.MultipleGradientPaint.CycleMethod;

import java.awt.Paint;

import java.awt.RadialGradientPaint;

import java.awt.TexturePaint;

import java.awt.geom.AffineTransform;

import java.awt.geom.Point2D;

import java.awt.geom.Rectangle2D;

import java.awt.image.AffineTransformOp;

import java.awt.image.BufferedImage;

import sun.awt.image.PixelConverter;

import sun.java2d.SunGraphics2D;

import sun.java2d.SurfaceData;

import sun.java2d.loops.CompositeType;

import sun.java2d.loops.SurfaceType;

import static sun.java2d.pipe.BufferedOpCodes.*;

public class BufferedPaints {

    static void setPaint(RenderQueue rq, SunGraphics2D sg2d,

                         Paint paint, int ctxflags)

    {

        if (sg2d.paintState <= SunGraphics2D.PAINT_ALPHACOLOR) {

            setColor(rq, sg2d.pixel);

        } else {

            boolean useMask = (ctxflags & BufferedContext.USE_MASK) != 0;

            switch (sg2d.paintState) {

            case SunGraphics2D.PAINT_GRADIENT:

                setGradientPaint(rq, sg2d,

                                 (GradientPaint)paint, useMask);

                break;

            case SunGraphics2D.PAINT_LIN_GRADIENT:

                setLinearGradientPaint(rq, sg2d,

                                       (LinearGradientPaint)paint, useMask);

                break;

            case SunGraphics2D.PAINT_RAD_GRADIENT:

                setRadialGradientPaint(rq, sg2d,

                                       (RadialGradientPaint)paint, useMask);

                break;

            case SunGraphics2D.PAINT_TEXTURE:

                setTexturePaint(rq, sg2d,

                                (TexturePaint)paint, useMask);

                break;

            default:

                break;

            }

        }

    }

    static void resetPaint(RenderQueue rq) {

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacity(4);

        RenderBuffer buf = rq.getBuffer();

        buf.putInt(RESET_PAINT);

    }

/****************************** Color support *******************************/

    private static void setColor(RenderQueue rq, int pixel) {

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacity(8);

        RenderBuffer buf = rq.getBuffer();

        buf.putInt(SET_COLOR);

        buf.putInt(pixel);

    }

/************************* 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);

    }

    private static void setGradientPaint(RenderQueue rq,

                                         SunGraphics2D sg2d,

                                         GradientPaint paint,

                                         boolean useMask)

    {

        setGradientPaint(rq, (AffineTransform)sg2d.transform.clone(),

                         paint.getColor1(), paint.getColor2(),

                         paint.getPoint1(), paint.getPoint2(),

                         paint.isCyclic(), useMask);

    }

/************************** TexturePaint support ****************************/

    /**

     * We use OpenGL's texture coordinate generator to automatically

     * map the TexturePaint image to the geometry being rendered.  The

     * generator uses two separate plane equations that take the (x,y)

     * location (in device space) of the fragment being rendered to

     * calculate (u,v) texture coordinates for that fragment:

     *     u = Ax + By + Cz + Dw

     *     v = Ex + Fy + Gz + Hw

     *

     * Since we use a 2D orthographic projection, we can assume that z=0

     * and w=1 for any fragment.  So we need to calculate appropriate

     * values for the plane equation constants (A,B,D) and (E,F,H) such

     * that {u,v}=0 for the top-left of the TexturePaint's anchor

     * rectangle and {u,v}=1 for the bottom-right of the anchor rectangle.

     * We can easily make the texture image repeat for {u,v} values

     * outside the range [0,1] by specifying the GL_REPEAT texture wrap

     * mode.

     *

     * Calculating the plane equation constants is surprisingly simple.

     * We can think of it as an inverse matrix operation that takes

     * device space coordinates and transforms them into user space

     * coordinates that correspond to a location relative to the anchor

     * rectangle.  First, we translate and scale the current user space

     * transform by applying the anchor rectangle bounds.  We then take

     * the inverse of this affine transform.  The rows of the resulting

     * inverse matrix correlate nicely to the plane equation constants

     * we were seeking.

     */

    private static void setTexturePaint(RenderQueue rq,

                                        SunGraphics2D sg2d,

                                        TexturePaint paint,

                                        boolean useMask)

    {

        BufferedImage bi = paint.getImage();

        SurfaceData dstData = sg2d.surfaceData;

        SurfaceData srcData =

            dstData.getSourceSurfaceData(bi, SunGraphics2D.TRANSFORM_ISIDENT,

                                         CompositeType.SrcOver, null);

        boolean filter =

            (sg2d.interpolationType !=

             AffineTransformOp.TYPE_NEAREST_NEIGHBOR);

        // calculate plane equation constants

        AffineTransform at = (AffineTransform)sg2d.transform.clone();

        Rectangle2D anchor = paint.getAnchorRect();

        at.translate(anchor.getX(), anchor.getY());

        at.scale(anchor.getWidth(), anchor.getHeight());

        double xp0, xp1, xp3, yp0, yp1, yp3;

        try {

            at.invert();

            xp0 = at.getScaleX();

            xp1 = at.getShearX();

            xp3 = at.getTranslateX();

            yp0 = at.getShearY();

            yp1 = at.getScaleY();

            yp3 = at.getTranslateY();

        } catch (java.awt.geom.NoninvertibleTransformException e) {

            xp0 = xp1 = xp3 = yp0 = yp1 = yp3 = 0.0;

        }

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacityAndAlignment(68, 12);

        RenderBuffer buf = rq.getBuffer();

        buf.putInt(SET_TEXTURE_PAINT);

        buf.putInt(useMask ? 1 : 0);

        buf.putInt(filter ? 1 : 0);

        buf.putLong(srcData.getNativeOps());

        buf.putDouble(xp0).putDouble(xp1).putDouble(xp3);

        buf.putDouble(yp0).putDouble(yp1).putDouble(yp3);

    }

/****************** Shared MultipleGradientPaint support ********************/

    /**

     * The maximum number of gradient "stops" supported by our native

     * fragment shader implementations.

     *

     * This value has been empirically determined and capped to allow

     * our native shaders to run on all shader-level graphics hardware,

     * even on the older, more limited GPUs.  Even the oldest Nvidia

     * hardware could handle 16, or even 32 fractions without any problem.

     * But the first-generation boards from ATI would fall back into

     * software mode (which is unusably slow) for values larger than 12;

     * it appears that those boards do not have enough native registers

     * to support the number of array accesses required by our gradient

     * shaders.  So for now we will cap this value at 12, but we can

     * re-evaluate this in the future as hardware becomes more capable.

     */

    /**

     * Helper function to convert a color component in sRGB space to

     * linear RGB space.  Copied directly from the

     * MultipleGradientPaintContext class.

     */

    public static int convertSRGBtoLinearRGB(int color) {

        float input, output;

        input = color / 255.0f;

        if (input <= 0.04045f) {

            output = input / 12.92f;

        } else {

            output = (float)Math.pow((input + 0.055) / 1.055, 2.4);

        }

        return Math.round(output * 255.0f);

    }

    /**

     * Helper function to convert a (non-premultiplied) Color in sRGB

     * space to an IntArgbPre pixel value, optionally in linear RGB space.

     * Based on the PixelConverter.ArgbPre.rgbToPixel() method.

     */

    private static int colorToIntArgbPrePixel(Color c, boolean linear) {

        int rgb = c.getRGB();

        if (!linear && ((rgb >> 24) == -1)) {

            return rgb;

        }

        int a = rgb >>> 24;

        int r = (rgb >> 16) & 0xff;

        int g = (rgb >>  8) & 0xff;

        int b = (rgb      ) & 0xff;

        if (linear) {

            r = convertSRGBtoLinearRGB(r);

            g = convertSRGBtoLinearRGB(g);

            b = convertSRGBtoLinearRGB(b);

        }

        int a2 = a + (a >> 7);

        r = (r * a2) >> 8;

        g = (g * a2) >> 8;

        b = (b * a2) >> 8;

        return ((a << 24) | (r << 16) | (g << 8) | (b));

    }

    /**

     * Converts the given array of Color objects into an int array

     * containing IntArgbPre pixel values.  If the linear parameter

     * is true, the Color values will be converted into a linear RGB

     * color space before being returned.

     */

    private static int[] convertToIntArgbPrePixels(Color[] colors,

                                                   boolean linear)

    {

        int[] pixels = new int[colors.length];

        for (int i = 0; i < colors.length; i++) {

            pixels[i] = colorToIntArgbPrePixel(colors[i], linear);

        }

        return pixels;

    }

/********************** LinearGradientPaint support *************************/

    /**

     * This method uses techniques that are nearly identical to those

     * employed in setGradientPaint() above.  The primary difference

     * is that at the native level we use a fragment shader to manually

     * apply the plane equation constants to the current fragment position

     * to calculate the gradient position in the range [0,1] (the native

     * code for GradientPaint does the same, except that it uses OpenGL's

     * automatic texture coordinate generation facilities).

     *

     * One other minor difference worth mentioning is that

     * setGradientPaint() calculates the plane equation constants

     * such that the gradient end points are positioned at 0.25 and 0.75

     * (for reasons discussed in the comments for that method).  In

     * contrast, for LinearGradientPaint we setup the equation constants

     * such that the gradient end points fall at 0.0 and 1.0.  The

     * reason for this difference is that in the fragment shader we

     * have more control over how the gradient values are interpreted

     * (depending on the paint's CycleMethod).

     */

    private static void setLinearGradientPaint(RenderQueue rq,

                                               SunGraphics2D sg2d,

                                               LinearGradientPaint paint,

                                               boolean useMask)

    {

        boolean linear =

            (paint.getColorSpace() == ColorSpaceType.LINEAR_RGB);

        Color[] colors = paint.getColors();

        int numStops = colors.length;

        Point2D pt1 = paint.getStartPoint();

        Point2D pt2 = paint.getEndPoint();

        AffineTransform at = paint.getTransform();

        at.preConcatenate(sg2d.transform);

        if (!linear && numStops == 2 &&

            paint.getCycleMethod() != CycleMethod.REPEAT)

        {

            // delegate to the optimized two-color gradient codepath

            boolean isCyclic =

                (paint.getCycleMethod() != CycleMethod.NO_CYCLE);

            setGradientPaint(rq, at,

                             colors[0], colors[1],

                             pt1, pt2,

                             isCyclic, useMask);

            return;

        }

        int cycleMethod = paint.getCycleMethod().ordinal();

        float[] fractions = paint.getFractions();

        int[] pixels = convertToIntArgbPrePixels(colors, linear);

        // 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(len, 1);

        // now gradient point 1 is at (0.0, 0), point 2 is at (1.0, 0)

        float p0, p1, p3;

        try {

            at.invert();

            p0 = (float)at.getScaleX();

            p1 = (float)at.getShearX();

            p3 = (float)at.getTranslateX();

        } catch (java.awt.geom.NoninvertibleTransformException e) {

            p0 = p1 = p3 = 0.0f;

        }

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacity(20 + 12 + (numStops*4*2));

        RenderBuffer buf = rq.getBuffer();

        buf.putInt(SET_LINEAR_GRADIENT_PAINT);

        buf.putInt(useMask ? 1 : 0);

        buf.putInt(linear  ? 1 : 0);

        buf.putInt(cycleMethod);

        buf.putInt(numStops);

        buf.putFloat(p0);

        buf.putFloat(p1);

        buf.putFloat(p3);

        buf.put(fractions);

        buf.put(pixels);

    }

/********************** RadialGradientPaint support *************************/

    /**

     * This method calculates six m** values and a focusX value that

     * are used by the native fragment shader.  These techniques are

     * based on a whitepaper by Daniel Rice on radial gradient performance

     * (attached to the bug report for 6521533).  One can refer to that

     * document for the complete set of formulas and calculations, but

     * the basic goal is to compose a transform that will convert an

     * (x,y) position in device space into a "u" value that represents

     * the relative distance to the gradient focus point.  The resulting

     * value can be used to look up the appropriate color by linearly

     * interpolating between the two nearest colors in the gradient.

     */

    private static void setRadialGradientPaint(RenderQueue rq,

                                               SunGraphics2D sg2d,

                                               RadialGradientPaint paint,

                                               boolean useMask)

    {

        boolean linear =

            (paint.getColorSpace() == ColorSpaceType.LINEAR_RGB);

        int cycleMethod = paint.getCycleMethod().ordinal();

        float[] fractions = paint.getFractions();

        Color[] colors = paint.getColors();

        int numStops = colors.length;

        int[] pixels = convertToIntArgbPrePixels(colors, linear);

        Point2D center = paint.getCenterPoint();

        Point2D focus = paint.getFocusPoint();

        float radius = paint.getRadius();

        // save original (untransformed) center and focus points

        double cx = center.getX();

        double cy = center.getY();

        double fx = focus.getX();

        double fy = focus.getY();

        // transform from gradient coords to device coords

        AffineTransform at = paint.getTransform();

        at.preConcatenate(sg2d.transform);

        focus = at.transform(focus, focus);

        // transform unit circle to gradient coords; we start with the

        // unit circle (center=(0,0), focus on positive x-axis, radius=1)

        // and then transform into gradient space

        at.translate(cx, cy);

        at.rotate(fx - cx, fy - cy);

        at.scale(radius, radius);

        // invert to get mapping from device coords to unit circle

        try {

            at.invert();

        } catch (Exception e) {

            at.setToScale(0.0, 0.0);

        }

        focus = at.transform(focus, focus);

        // clamp the focus point so that it does not rest on, or outside

        // of, the circumference of the gradient circle

        fx = Math.min(focus.getX(), 0.99);

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacity(20 + 28 + (numStops*4*2));

        RenderBuffer buf = rq.getBuffer();

        buf.putInt(SET_RADIAL_GRADIENT_PAINT);

        buf.putInt(useMask ? 1 : 0);

        buf.putInt(linear  ? 1 : 0);

        buf.putInt(numStops);

        buf.putInt(cycleMethod);

        buf.putFloat((float)at.getScaleX());

        buf.putFloat((float)at.getShearX());

        buf.putFloat((float)at.getTranslateX());