/* XGraphics.java -- The Graphics implementation for X
   Copyright (C) 2006 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath 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 for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package gnu.java.awt.peer.x;

import gnu.x11.Colormap;
import gnu.x11.Data;
import gnu.x11.Display;
import gnu.x11.Drawable;
import gnu.x11.GC;
import gnu.x11.Pixmap;
import gnu.x11.Point;
import gnu.x11.image.ZPixmap;

import java.awt.AWTError;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.Shape;
import java.awt.Toolkit;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;
import java.awt.image.ImageProducer;
import java.text.AttributedCharacterIterator;
import java.util.HashMap;

public class XGraphics
  extends Graphics
  implements Cloneable
{

  /**
   * The X Drawable to draw on.
   */
  private Drawable xdrawable;

  /**
   * The X graphics context (GC).
   */
  private GC xgc;

  /**
   * The current translation.
   */
  private int translateX;
  private int translateY;

  /**
   * The current clip. Possibly null.
   */
  private Rectangle clip;

  /**
   * The current font, possibly null.
   */
  private Font font;

  /**
   * The current foreground color, possibly null.
   */
  private Color foreground;

  /**
   * Indicates if this object has been disposed.
   */
  private boolean disposed = false;

  // TODO: Workaround for limitation in current Escher.
  private Pixmap.Format pixmapFormat;
  private int imageByteOrder;
  private int pixelByteCount;
  
  /**
   * Creates a new XGraphics on the specified X Drawable.
   *
   * @param d the X Drawable for which we create the Graphics
   */
  XGraphics(Drawable d)
  {
    xdrawable = d;
    xgc = new GC(d);
    translateX = 0;
    translateY = 0;
    clip = new Rectangle(0, 0, d.width, d.height);

    Display display = xdrawable.display;
    pixmapFormat = display.default_pixmap_format;
    imageByteOrder = display.image_byte_order;
    pixelByteCount = pixmapFormat.bits_per_pixel () / 8;
  }

  /**
   * Creates an exact copy of this graphics context.
   *
   * @return an exact copy of this graphics context
   */
  public Graphics create()
  {
    XGraphics copy = (XGraphics) clone();
    return copy;
  }

  /**
   * Translates the origin by (x, y).
   */
  public void translate(int x, int y)
  {
    translateX += x;
    translateY += y;
    if (clip != null)
      {
        clip.x -= x;
        clip.y -= y;
      }
  }

  /**
   * Returns the current foreground color, possibly <code>null</code>.
   *
   * @return the current foreground color, possibly <code>null</code>
   */
  public Color getColor()
  {
    return foreground;
  }

  /**
   * Sets the current foreground color. A <code>null</code> value doesn't
   * change the current setting.
   *
   * @param c the foreground color to set
   */
  public void setColor(Color c)
  {
    if (c != null)
      {
        XToolkit tk = (XToolkit) Toolkit.getDefaultToolkit();
        HashMap colorMap = tk.colorMap;
        gnu.x11.Color col = (gnu.x11.Color) colorMap.get(c);
        if (col == null)
          {
            Colormap map = xdrawable.display.default_colormap;
            col = map.alloc_color (c.getRed() * 256,
                                   c.getGreen() * 256,
                                   c.getBlue() * 256);
            colorMap.put(c, col);
          }
        xgc.set_foreground(col);
        foreground = c;
      }
  }

  public void setPaintMode()
  {
    // FIXME: Implement this.
    throw new UnsupportedOperationException("Not yet implemented");
  }

  public void setXORMode(Color color)
  {
    // FIXME: Implement this.
    throw new UnsupportedOperationException("Not yet implemented");
  }

  /**
   * Returns the current font, possibly <code>null</code>.
   *
   * @return the current font, possibly <code>null</code>
   */
  public Font getFont()
  {
    return font;
  }

  /**
   * Sets the font on the graphics context. A <code>null</code> value doesn't
   * change the current setting.
   *
   * @param f the font to set
   */
  public void setFont(Font f)
  {
    if (f != null)
      {
        XFontPeer xFontPeer = (XFontPeer) f.getPeer();
        xgc.set_font(xFontPeer.getXFont());
        font = f;
      }
  }

  /**
   * Returns the font metrics for the specified font.
   *
   * @param font the font for which we want the font metrics
   *
   * @return the font metrics for the specified font
   */
  public FontMetrics getFontMetrics(Font font)
  {
    if (font == null)
      {
        if (this.font == null)
          setFont(new Font("Dialog", Font.PLAIN, 12));
        font = this.font;
      }
    XFontPeer xFontPeer = (XFontPeer) font.getPeer();
    return xFontPeer.getFontMetrics(font);
  }

  /**
   * Returns the bounds of the current clip.
   *
   * @return the bounds of the current clip
   */
  public Rectangle getClipBounds()
  {
    return clip != null ? clip.getBounds() : null;
  }

  /**
   * Clips the current clip with the specified clip.
   */
  public void clipRect(int x, int y, int width, int height)
  {
    if (clip == null)
      {
        clip = new Rectangle(x, y, width, height);
      }
    else
      {
        computeIntersection(x, y, width, height, clip);
      }
    // Update the X clip setting.
    setXClip(clip.x, clip.y, clip.width, clip.height);
  }

  /**
   * Returns <code>true</code> when the specified rectangle intersects with
   * the current clip, <code>false</code> otherwise. This is overridden to
   * avoid unnecessary creation of Rectangles via getBounds().
   *
   * @param x the x coordinate of the rectangle
   * @param y the y coordinate of the rectangle
   * @param w the width of the rectangle
   * @param h the height of the rectangle
   *
   * @return <code>true</code> when the specified rectangle intersects with
   *         the current clip, <code>false</code> otherwise
   */
  public boolean hitClip(int x, int y, int w, int h)
  {
    boolean hit;
    if (clip == null)
      {
        hit = true;
      }
    else
      {
        // It's easier to determine if the rectangle lies outside the clip,
        // so we determine that and reverse the result (if it's not completely
        // outside, it most likely hits the clip rectangle).
        int x2 = x + w;
        int y2 = y + h;
        int clipX2 = clip.x + clip.width;
        int clipY2 = clip.y + clip.height;
        boolean outside = (x < clip.x && x2 < clip.x)     // Left.
                          || (x > clipX2  && x2 > clipX2) // Right.
                          || (y < clip.y && y2 < clip.y)  // Top.
                          || (y > clipY2 && y2 > clipY2); // Bottom.
        hit = ! outside;
      }
    return hit;
  }

  public void setClip(int x, int y, int width, int height)
  {
    if (clip != null)
      clip.setBounds(x, y, width, height);
    else
      clip = new Rectangle(x, y, width, height);
    setXClip(clip.x, clip.y, clip.width, clip.height);
  }

  /**
   * Sets the clip on the X server GC. The coordinates are not yet translated,
   * this will be performed by the X server.
   *
   * @param x the clip, X coordinate
   * @param y the clip, Y coordinate
   * @param w the clip, width
   * @param h the clip, height
   */
  private void setXClip(int x, int y, int w, int h)
  {
    gnu.x11.Rectangle[] clipRects = new gnu.x11.Rectangle[] {
                                  new gnu.x11.Rectangle(x, y, w, h) };
    xgc.set_clip_rectangles(translateX, translateY, clipRects, GC.YX_BANDED);
  }

  public Shape getClip()
  {
    // Return a copy here, so nobody can trash our clip.
    return clip == null ? null : clip.getBounds();
  }

  /**
   * Sets the current clip.
   *
   * @param c the clip to set
   */
  public void setClip(Shape c)
  {
    if (c != null)
      {
        Rectangle b;
        if (c instanceof Rectangle)
          {
            b = (Rectangle) c;
          }
        else
          {
            b = c.getBounds();
          }
        clip.setBounds(b);
        setXClip(b.x, b.y, b.width, b.height);
      }
    else
      {
        clip.setBounds(0, 0, xdrawable.width, xdrawable.height);
        setXClip(0, 0, xdrawable.width, xdrawable.height);
      }
  }

  public void copyArea(int x, int y, int width, int height, int dx, int dy)
  {
    // Clip and translate src rectangle.
    int srcX = Math.min(Math.max(x, clip.x), clip.x + clip.width)
               + translateX;
    int srcY = Math.min(Math.max(y, clip.y), clip.y + clip.height)
               + translateY;
    int srcWidth = Math.min(Math.max(x + width, clip.x),
                            clip.x + clip.width) - x;
    int srcHeight = Math.min(Math.max(y + height, clip.y),
                            clip.y + clip.height) - y;
    xdrawable.copy_area(xdrawable, xgc, srcX, srcY, srcWidth, srcHeight,
                        srcX + dx, srcY + dy);
  }

  /**
   * Draws a line from point (x1, y1) to point (x2, y2).
   */
  public void drawLine(int x1, int y1, int x2, int y2)
  {
    //System.err.println("drawLine: " + (x1 + translateX) + ", " + ( y1 + translateY) + ", " + (x2 + translateX) + ", " + (y2 + translateY) + " on: " + xdrawable);
    xdrawable.line(xgc, x1 + translateX, y1 + translateY,
                   x2 + translateX, y2 + translateY);
  }

  /**
   * Fills the specified rectangle.
   */
  public void fillRect(int x, int y, int width, int height)
  {
    xdrawable.rectangle(xgc, x + translateX, y + translateY,
                        width, height, true);
  }

  public void clearRect(int x, int y, int width, int height)
  {
    xgc.set_foreground(Color.WHITE.getRGB());
    xdrawable.rectangle(xgc, x, y, width, height, true);
    if (foreground != null)
      xgc.set_foreground(foreground.getRGB());
  }

  public void drawRoundRect(int x, int y, int width, int height, int arcWidth,
                            int arcHeight)
  {
    // Draw 4 lines.
    int arcRadiusX = arcWidth / 2;
    int arcRadiusY = arcHeight / 2;
    drawLine(x + arcRadiusX, y, x + width - arcRadiusX, y);
    drawLine(x, y + arcRadiusY, x, y + height - arcRadiusY);
    drawLine(x + arcRadiusX, y + height, x + width - arcRadiusX, y + height);
    drawLine(x + width, y + arcRadiusY, x + width, y + height - arcRadiusY);

    // Draw the 4 arcs at the corners.
    // Upper left.
    drawArc(x, y, arcWidth, arcHeight, 90, 90);
    // Lower left.
    drawArc(x, y + height - arcHeight, arcWidth, arcHeight, 180, 90);
    // Upper right.
    drawArc(x + width - arcWidth, y, arcWidth, arcHeight, 0, 90);
    // Lower right.
    drawArc(x + width - arcWidth, y + height - arcHeight, arcWidth, arcHeight,
            270, 90);
  }

  public void fillRoundRect(int x, int y, int width, int height, int arcWidth,
                            int arcHeight)
  {
    // Fill the 3 rectangles that make up the inner area.
    int arcRadiusX = arcWidth / 2;
    int arcRadiusY = arcHeight / 2;
    // Left.
    fillRect(x, y + arcRadiusY, arcRadiusX, height - arcHeight);
    // Middle.
    fillRect(x + arcRadiusX, y, width - arcWidth, height);
    // Right.
    fillRect(x + width - arcRadiusX, y + arcRadiusY, arcRadiusX,
             height - arcHeight);

    // Fill the 4 arcs in the corners.
    // Upper left.
    fillArc(x, y, arcWidth, arcHeight, 90, 90);
    // Lower left.
    fillArc(x, y + height - arcHeight, arcWidth, arcHeight, 180, 90);
    // Upper right.
    fillArc(x + width - arcWidth, y, arcWidth, arcHeight, 0, 90);
    // Lower right.
    fillArc(x + width - arcWidth, y + height - arcHeight, arcWidth, arcHeight,
            270, 90);
  }

  public void drawOval(int x, int y, int width, int height)
  {
    xdrawable.arc(xgc, x, y, width, height, 0, 360 * 64, false);
  }

  public void fillOval(int x, int y, int width, int height)
  {
    xdrawable.arc(xgc, x, y, width, height, 0, 360 * 64, true);
  }

  public void drawArc(int x, int y, int width, int height, int arcStart,
                      int arcAngle)
  {
    xdrawable.arc(xgc, x, y, width, height, arcStart * 64, arcAngle * 64, false);
  }

  public void fillArc(int x, int y, int width, int height, int arcStart,
                      int arcAngle)
  {
    xdrawable.arc(xgc, x, y, width, height, arcStart * 64, arcAngle * 64, true);
  }

  public void drawPolyline(int[] xPoints, int[] yPoints, int npoints)
  {
    int numPoints = Math.min(xPoints.length, yPoints.length);
    Point[] points = new Point[numPoints];
    // FIXME: Improve Escher API to accept arrays to avoid creation
    // of many Point objects.
    for (int i = 0; i < numPoints; i++)
      points[i] = new Point(xPoints[i], yPoints[i]);
    xdrawable.poly_line(xgc, points, Drawable.ORIGIN);
  }

  public void drawPolygon(int[] xPoints, int[] yPoints, int npoints)
  {
    int numPoints = Math.min(xPoints.length, yPoints.length);
    Point[] points = new Point[numPoints];
    // FIXME: Improve Escher API to accept arrays to avoid creation
    // of many Point objects.
    for (int i = 0; i < numPoints; i++)
      points[i] = new Point(xPoints[i], yPoints[i]);
    xdrawable.poly_line(xgc, points, Drawable.ORIGIN);
  }

  public void fillPolygon(int[] xPoints, int[] yPoints, int npoints)
  {
    int numPoints = Math.min(xPoints.length, yPoints.length);
    Point[] points = new Point[numPoints];
    // FIXME: Improve Escher API to accept arrays to avoid creation
    // of many Point objects.
    for (int i = 0; i < numPoints; i++)
      points[i] = new Point(xPoints[i], yPoints[i]);
    xdrawable.fill_poly(xgc, points, Drawable.COMPLEX, Drawable.ORIGIN);
  }

  /**
   * Draws the specified string at (x, y).
   */
  public void drawString(String string, int x, int y)
  {
    if (disposed)
      throw new AWTError("XGraphics already disposed");

    xdrawable.text(xgc, x + translateX, y + translateY, string);
  }

  public void drawString(AttributedCharacterIterator ci, int x, int y)
  {
    // FIXME: Implement this.
    throw new UnsupportedOperationException("Not yet implemented");
  }

  /**
   * Draws the specified image on the drawable at position (x,y).
   */
  public boolean drawImage(Image image, int x, int y, ImageObserver observer)
  {
    if (image instanceof XImage)
      {
        XImage xim = (XImage) image;
        Pixmap pm = xim.pixmap;
        xdrawable.copy_area(pm, xgc, 0, 0, pm.width, pm.height,
                            x + translateX, y + translateY);
      }
    else if (image instanceof BufferedImage
        && ((BufferedImage) image).getTransparency() != Transparency.OPAQUE)
      {
        BufferedImage bi = (BufferedImage) image;
        int width = bi.getWidth();
        int height = bi.getHeight();
        Data img = xdrawable.image(x + translateX, y + translateY,
                                   width, height, 0xFFFFFFFF, 2);

        // Compute line byte count.
        int lineBitCount = width * pixmapFormat.bits_per_pixel ();
        int rem = lineBitCount % pixmapFormat.scanline_pad ();
        int linePadCount = lineBitCount / pixmapFormat.scanline_pad ()
                             + (rem == 0 ? 0 : 1);
        int lineByteCount = linePadCount * pixmapFormat.scanline_pad () / 8;

        // Composite source and destination pixel data.
        int[] trgb = new int[3]; // The device rgb pixels.
        for (int yy = 0; yy < height; yy++)
          {
            for (int xx = 0; xx < width; xx++)
              {
                getRGB(xx, yy, img, trgb, lineByteCount);
                int srgb = bi.getRGB(xx, yy);
                float alpha = ((srgb >> 24) & 0xff) / 256F;
                float tAlpha = 1.F - alpha;
                int red = (srgb >> 16) & 0xFF;
                int green = (srgb >> 8) & 0xFF;
                int blue = (srgb) & 0xFF;
                trgb[0] = (int) (trgb[0] * tAlpha + red * alpha);
                trgb[1] = (int) (trgb[1] * tAlpha + green * alpha);
                trgb[2] = (int) (trgb[2] * tAlpha + blue * alpha);
                setRGB(xx, yy, img, trgb, lineByteCount);
              }
          }

        // Now we have the transparent image composited onto the target
        // Image, now we only must copy it to the Drawable.
        ZPixmap pm = new ZPixmap(xdrawable.display);
        pm.width = width;
        pm.height = height;
        pm.init();
        System.arraycopy(img.data, 32, pm.data, 0, img.data.length - 32);
        xdrawable.put_image(xgc, pm, x + translateX, y + translateY);
      }
    else
      {
        // Pre-render the image into an XImage.
        ImageProducer source = image.getSource();
        ImageConverter conv = new ImageConverter();
        source.startProduction(conv);
        XImage xim = conv.getXImage();
        Pixmap pm = xim.pixmap;
        xdrawable.copy_area(pm, xgc, 0, 0, pm.width, pm.height,
                            x + translateX, y + translateY);
      }
    return true;
  }

  /**
   * Helper method to work around limitation in the current Escher impl.
   *
   * @param x the x position
   * @param y the y position
   * @param img the image data
   * @param rgb an 3-size array that holds the rgb values on method exit
   */
  private void getRGB(int x, int y, Data img, int[] rgb, int lineByteCount)
  {
    // TODO: Does this also work on non-RGB devices?
    int i = y * lineByteCount + pixelByteCount * x;
    if (imageByteOrder == gnu.x11.image.Image.LSB_FIRST)
      {//if (i >= 5716-33) System.err.println("lbc: " + lineByteCount + ", " + pixelByteCount);
        rgb[2] = img.data[32 + i];
        rgb[1] = img.data[32 + i + 1];
        rgb[0] = img.data[32 + i + 2];
      }
    else
      {                    // MSB_FIRST
        rgb[0] = img.data[32 + i];
        rgb[1] = img.data[32 + i + 1];
        rgb[2] = img.data[32 + i + 2];
      }

  }

  /**
   * Helper method to work around limitation in the current Escher impl.
   *
   * @param x the x position
   * @param y the y position
   * @param img the image data
   * @param rgb an 3-size array that holds the rgb values on method exit
   */
  private void setRGB(int x, int y, Data img, int[] rgb, int lineByteCount)
  {
    // TODO: Does this also work on non-RGB devices?
    int i = y * lineByteCount + pixelByteCount * x;
    if (imageByteOrder == gnu.x11.image.Image.LSB_FIRST)
      {
        img.data[32 + i] = (byte) rgb[2];
        img.data[32 + i + 1] = (byte) rgb[1];
        img.data[32 + i + 2] = (byte) rgb[0];
      }
    else
      {                    // MSB_FIRST
        img.data[32 + i] = (byte) rgb[0];
        img.data[32 + i + 1] = (byte) rgb[1];
        img.data[32 + i + 2] = (byte) rgb[2];
      }
  }

  public boolean drawImage(Image image, int x, int y, int width, int height,
                           ImageObserver observer)
  {
    // FIXME: Implement this.
    throw new UnsupportedOperationException("Not yet implemented");
  }

  public boolean drawImage(Image image, int x, int y, Color bgcolor,
                           ImageObserver observer)
  {
    // FIXME: Implement this.
    throw new UnsupportedOperationException("Not yet implemented");
  }

  public boolean drawImage(Image image, int x, int y, int width, int height,
                           Color bgcolor, ImageObserver observer)
  {
    // FIXME: Implement this.
    throw new UnsupportedOperationException("Not yet implemented");
  }

  public boolean drawImage(Image image, int dx1, int dy1, int dx2, int dy2,
                           int sx1, int sy1, int sx2, int sy2,
                           ImageObserver observer)
  {
    return drawImage(image, dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2, null,
                     observer);
  }

  public boolean drawImage(Image image, int dx1, int dy1, int dx2, int dy2,
                           int sx1, int sy1, int sx2, int sy2, Color bgcolor,
                           ImageObserver observer)
  {

    // FIXME: What to do with bgcolor?

    // Scale the image.
    int sw = image.getWidth(observer);
    int sh = image.getHeight(observer);
    double scaleX = Math.abs(dx2 - dx1) / (double) Math.abs(sx2 - sx1);
    double scaleY = Math.abs(dy2 - dy1) / (double) Math.abs(sy2 - sy1);
    Image scaled = image.getScaledInstance((int) (scaleX * sw),
                                           (int) (scaleY * sh),
                                           Image.SCALE_FAST);

    // Scaled source coordinates.
    int sx1s = (int) (scaleX * Math.min(sx1, sx2));
    int sx2s = (int) (scaleX * Math.max(sx1, sx2));

    // Temporarily clip to the target rectangle.
    Rectangle old = clip;
    clipRect(dx1, dy1, dx2 - dx1, dy2 - dy1);

    // Draw scaled image.
    boolean res = drawImage(scaled, dx1 - sx1s, dy1 - sx2s, observer);

    // Reset clip.
    setClip(old);

    return res;
  }

  /**
   * Frees any resources associated with this object.
   */
  public void dispose()
  {
    if (! disposed)
      {
        xgc.free();
        xdrawable.display.flush();
        disposed = true;
      }
  }

  // Additional helper methods.

  /**
   * Creates and returns an exact copy of this XGraphics.
   */
  protected Object clone()
  {
    try
      {
        XGraphics copy = (XGraphics) super.clone();
        copy.xgc = xgc.copy();
        if (clip != null)
          {
            copy.clip = new Rectangle(clip);
            copy.setXClip(clip.x, clip.y, clip.width, clip.height);
          }
        return copy;
      }
    catch (CloneNotSupportedException ex)
      {
        assert false;
      }
    return null;
  }
  
  /**
   * Computes the intersection between two rectangles and stores the result
   * int the second rectangle.
   *
   * This method has been copied from {@link javax.swing.SwingUtilities}.
   *
   * @param x the x coordinate of the rectangle #1
   * @param y the y coordinate of the rectangle #1
   * @param w the width of the rectangle #1
   * @param h the height of the rectangle #1
   * @param rect the rectangle #2 and output rectangle
   */
  private static void computeIntersection(int x, int y, int w, int h,
                                          Rectangle rect)
  {
    int x2 = (int) rect.x;
    int y2 = (int) rect.y;
    int w2 = (int) rect.width;
    int h2 = (int) rect.height;

    int dx = (x > x2) ? x : x2;
    int dy = (y > y2) ? y : y2;
    int dw = (x + w < x2 + w2) ? (x + w - dx) : (x2 + w2 - dx);
    int dh = (y + h < y2 + h2) ? (y + h - dy) : (y2 + h2 - dy);

    if (dw >= 0 && dh >= 0)
      rect.setBounds(dx, dy, dw, dh);
    else
      rect.setBounds(0, 0, 0, 0);
  }


}