--- /dev/null
+// Copyright (C) 2003 Adam Megacz <adam@ibex.org> all rights reserved.
+//
+// You may modify, copy, and redistribute this code under the terms of
+// the GNU Library Public License version 2.1, with the exception of
+// the portion of clause 6a after the semicolon (aka the "obnoxious
+// relink clause")
+
+package org.ibex.util;
+
+/**
+ * A general-purpose data structure for holding a list of rectangular
+ * regions that need to be repainted, with intelligent coalescing.
+ *
+ * DirtyList will unify two regions A and B if the smallest rectangle
+ * enclosing both A and B occupies no more than epsilon + Area_A +
+ * Area_B. Failing this, if two corners of A fall within B, A will be
+ * shrunk to exclude the union of A and B.
+ */
+public class DirtyList {
+
+ public DirtyList() { }
+
+ /** The dirty regions (each one is an int[4]). */
+ private int[][] dirties = new int[10][];
+
+ /** The number of dirty regions */
+ private int numdirties = 0;
+
+ /** See class comment */
+ private static final int epsilon = 50 * 50;
+
+ public int num() { return numdirties; }
+
+ /** grows the array */
+ private void grow() {
+ int[][] newdirties = new int[dirties.length * 2][];
+ System.arraycopy(dirties, 0, newdirties, 0, numdirties);
+ dirties = newdirties;
+ }
+
+ /** Add a new rectangle to the dirty list; returns false if the
+ * region fell completely within an existing rectangle or set of
+ * rectangles (ie did not expand the dirty area)
+ */
+ public synchronized boolean dirty(int x, int y, int w, int h) {
+ if (numdirties == dirties.length) grow();
+
+ // we attempt the "lossless" combinations first
+ for(int i=0; i<numdirties; i++) {
+ int[] cur = dirties[i];
+
+ // new region falls completely within existing region
+ if (x >= cur[0] && y >= cur[1] && x + w <= cur[0] + cur[2] && y + h <= cur[1] + cur[3]) {
+ return false;
+
+ // existing region falls completely within new region
+ } else if (x <= cur[0] && y <= cur[1] && x + w >= cur[0] + cur[2] && y + h >= cur[1] + cur[3]) {
+ dirties[i][2] = 0;
+ dirties[i][3] = 0;
+
+ // left end of new region falls within existing region
+ } else if (x >= cur[0] && x < cur[0] + cur[2] && y >= cur[1] && y + h <= cur[1] + cur[3]) {
+ w = x + w - (cur[0] + cur[2]);
+ x = cur[0] + cur[2];
+ i = -1; continue;
+
+ // right end of new region falls within existing region
+ } else if (x + w > cur[0] && x + w <= cur[0] + cur[2] && y >= cur[1] && y + h <= cur[1] + cur[3]) {
+ w = cur[0] - x;
+ i = -1; continue;
+
+ // top end of new region falls within existing region
+ } else if (x >= cur[0] && x + w <= cur[0] + cur[2] && y >= cur[1] && y < cur[1] + cur[3]) {
+ h = y + h - (cur[1] + cur[3]);
+ y = cur[1] + cur[3];
+ i = -1; continue;
+
+ // bottom end of new region falls within existing region
+ } else if (x >= cur[0] && x + w <= cur[0] + cur[2] && y + h > cur[1] && y + h <= cur[1] + cur[3]) {
+ h = cur[1] - y;
+ i = -1; continue;
+
+ // left end of existing region falls within new region
+ } else if (dirties[i][0] >= x && dirties[i][0] < x + w && dirties[i][1] >= y && dirties[i][1] + dirties[i][3] <= y + h) {
+ dirties[i][2] = dirties[i][2] - (x + w - dirties[i][0]);
+ dirties[i][0] = x + w;
+ i = -1; continue;
+
+ // right end of existing region falls within new region
+ } else if (dirties[i][0] + dirties[i][2] > x && dirties[i][0] + dirties[i][2] <= x + w &&
+ dirties[i][1] >= y && dirties[i][1] + dirties[i][3] <= y + h) {
+ dirties[i][2] = x - dirties[i][0];
+ i = -1; continue;
+
+ // top end of existing region falls within new region
+ } else if (dirties[i][0] >= x && dirties[i][0] + dirties[i][2] <= x + w && dirties[i][1] >= y && dirties[i][1] < y + h) {
+ dirties[i][3] = dirties[i][3] - (y + h - dirties[i][1]);
+ dirties[i][1] = y + h;
+ i = -1; continue;
+
+ // bottom end of existing region falls within new region
+ } else if (dirties[i][0] >= x && dirties[i][0] + dirties[i][2] <= x + w &&
+ dirties[i][1] + dirties[i][3] > y && dirties[i][1] + dirties[i][3] <= y + h) {
+ dirties[i][3] = y - dirties[i][1];
+ i = -1; continue;
+ }
+
+ }
+
+ // then we attempt the "lossy" combinations
+ for(int i=0; i<numdirties; i++) {
+ int[] cur = dirties[i];
+ if (w > 0 && h > 0 && cur[2] > 0 && cur[3] > 0 &&
+ ((max(x + w, cur[0] + cur[2]) - min(x, cur[0])) *
+ (max(y + h, cur[1] + cur[3]) - min(y, cur[1])) <
+ w * h + cur[2] * cur[3] + epsilon)) {
+ int a = min(cur[0], x);
+ int b = min(cur[1], y);
+ int c = max(x + w, cur[0] + cur[2]) - min(cur[0], x);
+ int d = max(y + h, cur[1] + cur[3]) - min(cur[1], y);
+ dirties[i][2] = 0;
+ dirties[i][3] = 0;
+ return dirty(a, b, c, d);
+ }
+ }
+
+ dirties[numdirties++] = new int[] { x, y, w, h };
+ return true;
+ }
+
+ /** Returns true if there are no regions that need repainting */
+ public boolean empty() { return (numdirties == 0); }
+
+ /**
+ * Atomically returns the list of dirty rectangles as an array of
+ * four-int arrays and clears the internal dirty-rectangle
+ * list. Note that some of the regions returned may be null, or
+ * may have zero height or zero width, and do not need to be
+ * repainted.
+ */
+ public synchronized int[][] flush() {
+ if (numdirties == 0) return null;
+ int[][] ret = dirties;
+ for(int i=numdirties; i<ret.length; i++) ret[i] = null;
+ dirties = new int[dirties.length][];
+ numdirties = 0;
+ return ret;
+ }
+
+ /** included here so that it can be inlined */
+ private static final int min(int a, int b) {
+ if (a<b) return a;
+ else return b;
+ }
+
+ /** included here so that it can be inlined */
+ private static final int max(int a, int b) {
+ if (a>b) return a;
+ else return b;
+ }
+
+ /** included here so that it can be inlined */
+ private static final int min(int a, int b, int c) {
+ if (a<=b && a<=c) return a;
+ else if (b<=c && b<=a) return b;
+ else return c;
+ }
+
+ /** included here so that it can be inlined */
+ private static final int max(int a, int b, int c) {
+ if (a>=b && a>=c) return a;
+ else if (b>=c && b>=a) return b;
+ else return c;
+ }
+
+ /** included here so that it can be inlined */
+ private static final int bound(int a, int b, int c) {
+ if (a > b) return a;
+ if (c < b) return c;
+ return b;
+ }
+
+}
projects / org.ibex.core.git / blobdiff