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Java example source code file (XScrollPanePeer.java)

This example Java source code file (XScrollPanePeer.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

awt, color, component, dimension, event, graphics, horizontal, margin, point, reflection, scrollbar, scrollpane, scrollpaneadjustable, space, vertical, xscrollpanecontentwindow, xwindow

The XScrollPanePeer.java Java example source code

/*
 * Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved.
 * 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.awt.X11;

import java.awt.*;
import java.awt.event.*;
import java.awt.peer.*;
import java.lang.reflect.*;

import sun.awt.AWTAccessor;

class XScrollPanePeer extends XComponentPeer implements ScrollPanePeer, XScrollbarClient {

    public final static int     MARGIN = 1;
    public final static int     SCROLLBAR;
    public final static int     SPACE = 2;
    public final static int     SCROLLBAR_INSET = 2;

    public final static int     VERTICAL = 1 << 0;
    public final static int     HORIZONTAL = 1 << 1;

    static {
        SCROLLBAR = XToolkit.getUIDefaults().getInt("ScrollBar.defaultWidth");
    }

    XVerticalScrollbar       vsb;
    XHorizontalScrollbar     hsb;
    XWindow                  clip;

    int                         active=VERTICAL;
    int                         hsbSpace;
    int                         vsbSpace;

    static class XScrollPaneContentWindow extends XWindow {
        XScrollPaneContentWindow(ScrollPane target, long parentWindow) {
            super(target, parentWindow);
        }
        public String getWMName() {
            return "ScrollPane content";
        }
    }

    XScrollPanePeer(ScrollPane target) {
        super(target);

        // Create the clip window. The field "clip" must be null when
        // we call winCreate, or the parent of clip will be set to itself!
        clip = null;


        XWindow c = new XScrollPaneContentWindow(target,window);
        clip = c;

        vsb = new XVerticalScrollbar(this);

        hsb = new XHorizontalScrollbar(this);

        if (target.getScrollbarDisplayPolicy() == ScrollPane.SCROLLBARS_ALWAYS) {
            vsbSpace = hsbSpace = SCROLLBAR;
        } else {
            vsbSpace = hsbSpace = 0;
        }

        int unitIncrement = 1;
        Adjustable vAdjustable = target.getVAdjustable();
        if (vAdjustable != null){
            unitIncrement = vAdjustable.getUnitIncrement();
        }
        int h = height-hsbSpace;
        vsb.setValues(0, h, 0, h, unitIncrement, Math.max(1, (int)(h * 0.90)));
        vsb.setSize(vsbSpace-SCROLLBAR_INSET, h);

        unitIncrement = 1;
        Adjustable hAdjustable = target.getHAdjustable();
        if (hAdjustable != null){
            unitIncrement = hAdjustable.getUnitIncrement();
        }
        int w = width - vsbSpace;
        hsb.setValues(0, w, 0, w, unitIncrement, Math.max(1, (int)(w * 0.90)));
        hsb.setSize(w, hsbSpace-SCROLLBAR_INSET);

        setViewportSize();
        clip.xSetVisible(true);


    }

    public long getContentWindow()
    {
        return (clip == null) ? window : clip.getWindow();
    }

    public void setBounds(int x, int y, int w, int h, int op) {
        super.setBounds(x, y, w, h, op);

        if (clip == null) return;
        setScrollbarSpace();
        setViewportSize();
        repaint();
    }

    public Insets getInsets() {
        return new Insets(MARGIN, MARGIN, MARGIN+hsbSpace, MARGIN+vsbSpace);
    }

    public int getHScrollbarHeight() {
        return SCROLLBAR;
    }

    public int getVScrollbarWidth() {
        return SCROLLBAR;
    }

    public void childResized(int w, int h) {
        if (setScrollbarSpace()) {
            setViewportSize();
        }
        repaint();
    }

    Dimension getChildSize() {
        ScrollPane sp = (ScrollPane)target;
        if (sp.countComponents() > 0) {
            Component c = sp.getComponent(0);
            return c.size();
        } else {
            return new Dimension(0, 0);
        }
    }

    boolean setScrollbarSpace() {
        ScrollPane sp = (ScrollPane)target;
        boolean changed = false;
        int sbDisplayPolicy = sp.getScrollbarDisplayPolicy();

        if (sbDisplayPolicy == ScrollPane.SCROLLBARS_NEVER) {
            return changed;
        }
        Dimension cSize = getChildSize();

        if (sbDisplayPolicy == ScrollPane.SCROLLBARS_AS_NEEDED) {
            int oldHsbSpace = hsbSpace;
            int oldVsbSpace = vsbSpace;
            hsbSpace = (cSize.width <= (width - 2*MARGIN) ? 0 : SCROLLBAR);
            vsbSpace = (cSize.height <= (height - 2*MARGIN) ? 0 : SCROLLBAR);

            if (hsbSpace == 0 && vsbSpace != 0) {
                hsbSpace = (cSize.width <= (width - SCROLLBAR - 2*MARGIN) ? 0 : SCROLLBAR);
            }
            if (vsbSpace == 0 && hsbSpace != 0) {
                vsbSpace = (cSize.height <= (height - SCROLLBAR - 2*MARGIN) ? 0 : SCROLLBAR);
            }
            if (oldHsbSpace != hsbSpace || oldVsbSpace != vsbSpace) {
                changed = true;
            }
        }
        if (vsbSpace > 0) {
            int vis = height - (2*MARGIN) - hsbSpace;
            int max = Math.max(cSize.height, vis);
            vsb.setValues(vsb.getValue(), vis, 0, max);
            vsb.setBlockIncrement((int)(vsb.getVisibleAmount() * .90));
            vsb.setSize(vsbSpace-SCROLLBAR_INSET, height-hsbSpace);
            // Adjustable vadj = sp.getVAdjustable();
            // vadj.setVisibleAmount(vsb.vis);
            // vadj.setMaximum(vsb.max);
            // vadj.setBlockIncrement(vsb.page);
        }
        if (hsbSpace > 0) {
            int vis = width - (2*MARGIN) - vsbSpace;
            int max = Math.max(cSize.width, vis);
            hsb.setValues(hsb.getValue(), vis, 0, max);
            hsb.setBlockIncrement((int)(hsb.getVisibleAmount() * .90));
            hsb.setSize(width-vsbSpace, hsbSpace-SCROLLBAR_INSET);
            // Adjustable hadj = sp.getHAdjustable();
            // hadj.setVisibleAmount(hsb.vis);
            // hadj.setMaximum(hsb.max);
            // hadj.setBlockIncrement(hsb.page);
        }

        // Check to see if we hid either of the scrollbars but left
        // ourselves scrolled off of the top and/or right of the pane.
        // If we did, we need to scroll to the top and/or right of of
        // the pane to make it visible.
        //
        // Reminder: see if there is a better place to put this code.
        boolean must_scroll = false;

        // Get the point at which the ScrollPane is currently located
        // if number of components > 0
        Point p = new Point(0, 0);

        if (((ScrollPane)target).getComponentCount() > 0){

            p = ((ScrollPane)target).getComponent(0).location();

            if ((vsbSpace == 0) && (p.y < 0)) {
                p.y = 0;
                must_scroll = true;
            }

            if ((hsbSpace == 0) && (p.x < 0)) {
                p.x = 0;
                must_scroll = true;
            }
        }

        if (must_scroll)
            scroll(x, y, VERTICAL | HORIZONTAL);

        return changed;
    }

    void setViewportSize() {
        clip.xSetBounds(MARGIN, MARGIN,
                width - (2*MARGIN)  - vsbSpace,
                height - (2*MARGIN) - hsbSpace);
    }

    public void setUnitIncrement(Adjustable adj, int u) {
        if (adj.getOrientation() == Adjustable.VERTICAL) {
            vsb.setUnitIncrement(u);
        } else {
            // HORIZONTAL
            hsb.setUnitIncrement(u);
        }
    }

    public void setValue(Adjustable adj, int v) {
        if (adj.getOrientation() == Adjustable.VERTICAL) {
            scroll(-1, v, VERTICAL);
        } else {
            // HORIZONTAL
            scroll(v, -1, HORIZONTAL);
        }
    }

    public void setScrollPosition(int x, int y) {
        scroll(x, y, VERTICAL | HORIZONTAL);
    }

    void scroll(int x, int y, int flag) {
        scroll(x, y, flag, AdjustmentEvent.TRACK);
    }

    /**
     * Scroll the contents to position x, y
     */
    void scroll(int x, int y, int flag, int type) {
        checkSecurity();
        ScrollPane sp = (ScrollPane)target;
        Component c = getScrollChild();
        if (c == null) {
            return;
        }
        int sx, sy;
        Color colors[] = getGUIcolors();

        if (sp.getScrollbarDisplayPolicy() == ScrollPane.SCROLLBARS_NEVER) {
            sx = -x;
            sy = -y;
        } else {
            Point p = c.location();
            sx = p.x;
            sy = p.y;

            if ((flag & HORIZONTAL) != 0) {
                hsb.setValue(Math.min(x, hsb.getMaximum()-hsb.getVisibleAmount()));
                ScrollPaneAdjustable hadj = (ScrollPaneAdjustable)sp.getHAdjustable();
                setAdjustableValue(hadj, hsb.getValue(), type);
                sx = -(hsb.getValue());
                Graphics g = getGraphics();
                if (g != null) {
                    try {
                        paintHorScrollbar(g, colors, true);
                    } finally {
                        g.dispose();
                    }
                }
            }
            if ((flag & VERTICAL) != 0) {
                vsb.setValue(Math.min(y, vsb.getMaximum() - vsb.getVisibleAmount()));
                ScrollPaneAdjustable vadj = (ScrollPaneAdjustable)sp.getVAdjustable();
                setAdjustableValue(vadj, vsb.getValue(), type);
                sy = -(vsb.getValue());
                Graphics g = getGraphics();
                if (g != null) {
                    try {
                        paintVerScrollbar(g, colors, true);
                    } finally {
                        g.dispose();
                    }
                }
            }
        }
        c.move(sx, sy);
    }

    private void setAdjustableValue(final ScrollPaneAdjustable adj, final int value,
                            final int type) {
        AWTAccessor.getScrollPaneAdjustableAccessor().setTypedValue(adj, value,
                                                                    type);
    }
    @Override
    void paintPeer(final Graphics g) {
        final Color[] colors = getGUIcolors();
        g.setColor(colors[BACKGROUND_COLOR]);
        final int h = height - hsbSpace;
        final int w = width - vsbSpace;
        g.fillRect(0, 0, w, h);
        // paint rectangular region between scrollbars
        g.fillRect(w, h, vsbSpace, hsbSpace);
        if (MARGIN > 0) {
            draw3DRect(g, colors, 0, 0, w - 1, h - 1, false);
        }
        paintScrollBars(g, colors);
    }
    private void paintScrollBars(Graphics g, Color[] colors) {
        if (vsbSpace > 0) {
            paintVerScrollbar(g, colors, true);
            // paint the whole scrollbar
        }

        if (hsbSpace > 0) {
            paintHorScrollbar(g, colors, true);
            // paint the whole scrollbar
        }
    }
    void repaintScrollBars() {
        Graphics g = getGraphics();
        Color colors[] = getGUIcolors();
        if (g != null) {
            try {
                paintScrollBars(g, colors);
            } finally {
                g.dispose();
            }
        }
    }
    public void repaintScrollbarRequest(XScrollbar sb) {
        Graphics g = getGraphics();
        Color colors[] = getGUIcolors();
        if (g != null) {
            try {
                if (sb == vsb) {
                    paintVerScrollbar(g, colors, true);
                } else if (sb == hsb) {
                    paintHorScrollbar(g, colors, true);
                }
            } finally {
                g.dispose();
            }
        }
    }
    public void handleEvent(java.awt.AWTEvent e) {
        super.handleEvent(e);

        int id = e.getID();
        switch(id) {
            case PaintEvent.PAINT:
            case PaintEvent.UPDATE:
                repaintScrollBars();
                break;
        }
    }


    /**
     * Paint the horizontal scrollbar to the screen
     *
     * @param g the graphics context to draw into
     * @param colors the colors used to draw the scrollbar
     * @param paintAll paint the whole scrollbar if true, just the thumb if false
     */
    void paintHorScrollbar(Graphics g, Color colors[], boolean paintAll) {
        if (hsbSpace <= 0) {
            return;
        }
        Graphics ng = g.create();
        g.setColor(colors[BACKGROUND_COLOR]);

        // SCROLLBAR is the height of scrollbar area
        // but the actual scrollbar is SCROLLBAR-SPACE high;
        // the rest must be filled with background color
        int w = width - vsbSpace - (2*MARGIN);
        g.fillRect(MARGIN, height-SCROLLBAR, w, SPACE);
        g.fillRect(0, height-SCROLLBAR, MARGIN, SCROLLBAR);
        g.fillRect(MARGIN + w, height-SCROLLBAR, MARGIN, SCROLLBAR);

        try {
            ng.translate(MARGIN, height - (SCROLLBAR - SPACE));
            hsb.paint(ng, colors, paintAll);
        }
        finally {
            ng.dispose();
        }


    }




    /**
     * Paint the vertical scrollbar to the screen
     *
     * @param g the graphics context to draw into
     * @param colors the colors used to draw the scrollbar
     * @param paintAll paint the whole scrollbar if true, just the thumb if false
     */
    void paintVerScrollbar(Graphics g, Color colors[], boolean paintAll) {
        if (vsbSpace <= 0) {
            return;
        }
        Graphics ng = g.create();
        g.setColor(colors[BACKGROUND_COLOR]);

        // SCROLLBAR is the width of scrollbar area
        // but the actual scrollbar is SCROLLBAR-SPACE wide;
        // the rest must be filled with background color
        int h = height - hsbSpace - (2*MARGIN);
        g.fillRect(width-SCROLLBAR, MARGIN, SPACE, h);
        g.fillRect(width-SCROLLBAR, 0, SCROLLBAR, MARGIN);
        g.fillRect(width-SCROLLBAR, MARGIN+h, SCROLLBAR, MARGIN);

        try {
            ng.translate(width - (SCROLLBAR - SPACE), MARGIN);
            vsb.paint(ng, colors, paintAll);
        }
        finally {
            ng.dispose();
        }
    }

    /**
     *
     * @see java.awt.event.MouseEvent
     * MouseEvent.MOUSE_CLICKED
     * MouseEvent.MOUSE_PRESSED
     * MouseEvent.MOUSE_RELEASED
     * MouseEvent.MOUSE_MOVED
     * MouseEvent.MOUSE_ENTERED
     * MouseEvent.MOUSE_EXITED
     * MouseEvent.MOUSE_DRAGGED
     */
    public void handleJavaMouseEvent( MouseEvent mouseEvent ) {
        super.handleJavaMouseEvent(mouseEvent);
        int modifiers = mouseEvent.getModifiers();
        int id = mouseEvent.getID();
        int x = mouseEvent.getX();
        int y = mouseEvent.getY();


        //        super.handleMouseEvent(mouseEvent);

        if ((modifiers & InputEvent.BUTTON1_MASK) == 0) {
            return;
        }

        switch (id) {
            case MouseEvent.MOUSE_PRESSED:
                if (inVerticalScrollbar(x,y )) {
                    active = VERTICAL;
                    int h = height - hsbSpace - (2*MARGIN);
                    vsb.handleMouseEvent(id,modifiers,x - (width - SCROLLBAR + SPACE),y-MARGIN);
                } else if (inHorizontalScrollbar(x, y) ) {
                    active = HORIZONTAL;
                    int w = width - 2*MARGIN - vsbSpace;
                    hsb.handleMouseEvent(id,modifiers,x-MARGIN,y-(height - SCROLLBAR + SPACE));
                }
                break;

                // On mouse up, pass the event through to the scrollbar to stop
                // scrolling. The x & y passed do not matter.
            case MouseEvent.MOUSE_RELEASED:
                //     winReleaseCursorFocus();
                if (active == VERTICAL) {
                    vsb.handleMouseEvent(id,modifiers,x,y);
                } else if (active == HORIZONTAL) {
                    hsb.handleMouseEvent(id,modifiers,x,y);
                }
                break;


            case MouseEvent.MOUSE_DRAGGED:
                if ((active == VERTICAL)) {
                    int h = height - 2*MARGIN - hsbSpace;
                    vsb.handleMouseEvent(id,modifiers,x-(width - SCROLLBAR + SPACE),y-MARGIN);
                } else if ((active == HORIZONTAL)) {
                    int w = width - 2*MARGIN - vsbSpace;
                    hsb.handleMouseEvent(id,modifiers,x-MARGIN,y-(height - SCROLLBAR + SPACE));
                }
                break;
        }
    }

    /**
     * return value from the scrollbar
     */
    public void notifyValue(XScrollbar obj, int type, int v, boolean isAdjusting) {
        if (obj == vsb) {
            scroll(-1, v, VERTICAL, type);
        } else if ((XHorizontalScrollbar)obj == hsb) {
            scroll(v, -1, HORIZONTAL, type);
        }
    }

    /**
     * return true if the x and y position is in the verticalscrollbar
     */
    boolean inVerticalScrollbar(int x, int y) {
        if (vsbSpace <= 0) {
            return false;
        }
        int h = height - MARGIN - hsbSpace;
        return (x >= width - (SCROLLBAR - SPACE)) && (x < width) && (y >= MARGIN) && (y < h);
    }

    /**
     * return true if the x and y position is in the horizontal scrollbar
     */
    boolean inHorizontalScrollbar(int x, int y) {
        if (hsbSpace <= 0) {
            return false;
        }
        int w = width - MARGIN - vsbSpace;
        return (x >= MARGIN) && (x < w) && (y >= height - (SCROLLBAR - SPACE)) && (y < height);
    }

    private Component getScrollChild() {
        ScrollPane sp = (ScrollPane)target;
        Component child = null;
        try {
            child = sp.getComponent(0);
        } catch (ArrayIndexOutOfBoundsException e) {
            // do nothing.  in this case we return null
        }
        return child;
    }

    int vval;
    int hval;
    int vmax;
    int hmax;
    /*
     * Print the native component by rendering the Motif look ourselves.
     * ToDo(aim): needs to query native motif for more accurate size and
     * color information.
     */
    public void print(Graphics g) {
        ScrollPane sp = (ScrollPane)target;
        Dimension d = sp.size();
        Color bg = sp.getBackground();
        Color fg = sp.getForeground();
        Point p = sp.getScrollPosition();
        Component c = getScrollChild();
        Dimension cd;
        if (c != null) {
            cd = c.size();
        } else {
            cd = new Dimension(0, 0);
        }
        int sbDisplay = sp.getScrollbarDisplayPolicy();
        int vvis, hvis, vmin, hmin, vmax, hmax, vval, hval;

        switch (sbDisplay) {
            case ScrollPane.SCROLLBARS_NEVER:
                hsbSpace = vsbSpace = 0;
                break;
            case ScrollPane.SCROLLBARS_ALWAYS:
                hsbSpace = vsbSpace = SCROLLBAR;
                break;
            case ScrollPane.SCROLLBARS_AS_NEEDED:
                hsbSpace = (cd.width <= (d.width - 2*MARGIN)? 0 : SCROLLBAR);
                vsbSpace = (cd.height <= (d.height - 2*MARGIN)? 0 : SCROLLBAR);

                if (hsbSpace == 0 && vsbSpace != 0) {
                    hsbSpace = (cd.width <= (d.width - SCROLLBAR - 2*MARGIN)? 0 : SCROLLBAR);
                }
                if (vsbSpace == 0 && hsbSpace != 0) {
                    vsbSpace = (cd.height <= (d.height - SCROLLBAR - 2*MARGIN)? 0 : SCROLLBAR);
                }
        }

        vvis = hvis = vmin = hmin = vmax = hmax = vval = hval = 0;

        if (vsbSpace > 0) {
            vmin = 0;
            vvis = d.height - (2*MARGIN) - hsbSpace;
            vmax = Math.max(cd.height - vvis, 0);
            vval = p.y;
        }
        if (hsbSpace > 0) {
            hmin = 0;
            hvis = d.width - (2*MARGIN) - vsbSpace;
            hmax = Math.max(cd.width - hvis, 0);
            hval = p.x;
        }

        // need to be careful to add the margins back in here because
        // we're drawing the margin border, after all!
        int w = d.width - vsbSpace;
        int h = d.height - hsbSpace;

        g.setColor(bg);
        g.fillRect(0, 0, d.width, d.height);

        if (hsbSpace > 0) {
            int sbw = d.width - vsbSpace;
            g.fillRect(1, d.height - SCROLLBAR - 3, sbw - 1, SCROLLBAR - 3);
            Graphics ng = g.create();
            try {
                ng.translate(0, d.height - (SCROLLBAR - 2));
                drawScrollbar(ng, bg, SCROLLBAR - 2, sbw,
                        hmin, hmax, hval, hvis, true);
            } finally {
                ng.dispose();
            }
        }
        if (vsbSpace > 0) {
            int sbh = d.height - hsbSpace;
            g.fillRect(d.width - SCROLLBAR - 3, 1, SCROLLBAR - 3, sbh - 1);
            Graphics ng = g.create();
            try {
                ng.translate(d.width - (SCROLLBAR - 2), 0);
                drawScrollbar(ng, bg, SCROLLBAR - 2, sbh,
                        vmin, vmax, vval, vvis, false);
            } finally {
                ng.dispose();
            }
        }

        draw3DRect(g, bg, 0, 0, w - 1, h - 1, false);

        target.print(g);
        sp.printComponents(g);
    }

}

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