GUAC-240: New rectangle helper methods and utilities which will be used by adaptive encoding. Rectangle helper unit tests.

src/common/guac_rect.c

@@ -80,3 +80,190 @@ void guac_common_rect_constrain(guac_common_rect* rect, const guac_common_rect*
 
 }
 
+int guac_common_rect_expand_to_grid(int cell_size, guac_common_rect* rect,
+                                    const guac_common_rect* max_rect) {
+
+    /* Invalid cell_size received */
+    if (cell_size <= 0)
+        return -1;
+
+    /* Nothing to do */
+    if (cell_size == 1)
+        return 0;
+
+    /* Calculate how much the rectangle must be adjusted to fit within the
+     * given cell size. */
+    int dw = cell_size - rect->width % cell_size;
+    int dh = cell_size - rect->height % cell_size;
+
+    int dx = dw / 2;
+    int dy = dh / 2;
+
+    /* Set initial extents of adjusted rectangle. */
+    int top = rect->y - dy;
+    int left = rect->x - dx;
+    int bottom = top + rect->height + dh;
+    int right = left + rect->width + dw;
+
+    /* The max rectangle */
+    int max_left   = max_rect->x;
+    int max_top    = max_rect->y;
+    int max_right  = max_left + max_rect->width;
+    int max_bottom = max_top  + max_rect->height;
+
+    /* If the adjusted rectangle has sides beyond the max rectangle, or is larger
+     * in any direction; shift or adjust the rectangle while trying to fit in
+     * the grid */
+
+    /* Adjust left/right */
+    if (right > max_right) {
+
+        /* shift to left */
+        dw = right - max_right;
+        right -= dw;
+        left -= dw;
+
+        /* clamp left if too far */
+        if (left < max_left) {
+            left = max_left;
+        }
+    }
+    else if (left < max_left) {
+
+        /* shift to right */
+        dw = max_left - left;
+        left += dw;
+        right += dw;
+
+        /* clamp right if too far */
+        if (right > max_right) {
+            right = max_right;
+        }
+    }
+
+    /* Adjust top/bottom */
+    if (bottom > max_bottom) {
+
+        /* shift up */
+        dh = bottom - max_bottom;
+        bottom -= dh;
+        top -= dh;
+
+        /* clamp top if too far */
+        if (top < max_top) {
+            top = max_top;
+        }
+    }
+    else if (top < max_top) {
+
+        /* shift down */
+        dh = max_top - top;
+        top += dh;
+        bottom += dh;
+
+        /* clamp bottom if too far */
+        if (bottom > max_bottom) {
+            bottom = max_bottom;
+        }
+    }
+
+    /* Commit rect */
+    guac_common_rect_init(rect, left, top, right - left, bottom - top);
+
+    return 0;
+
+}
+
+int guac_common_rect_intersects(const guac_common_rect* rect,
+                                const guac_common_rect* other) {
+
+    /* Empty (no intersection) */
+    if (other->x + other->width < rect->x || rect->x + rect->width < other->x ||
+        other->y + other->height < rect->y || rect->y + rect->height < other->y) {
+        return 0;
+    }
+    /* Complete */
+    else if (other->x <= rect->x && (other->x + other->width) >= (rect->x + rect->width) &&
+        other->y <= rect->y && (other->y + other->height) >= (rect->y + rect->height)) {
+        return 2;
+    }
+    /* Partial intersection */
+    return 1;
+
+}
+
+int guac_common_rect_clip_and_split(guac_common_rect* rect,
+        const guac_common_rect* hole, guac_common_rect* split_rect) {
+
+    /* Only continue if the rectangles intersects */
+    if (!guac_common_rect_intersects(rect, hole))
+        return 0;
+
+    int top, left, bottom, right;
+
+    /* Clip and split top */
+    if (rect->y < hole->y) {
+        top = rect->y;
+        left = rect->x;
+        bottom = hole->y;
+        right = rect->x + rect->width;
+        guac_common_rect_init(split_rect, left, top, right - left, bottom - top);
+
+        /* Re-initialize original rect */
+        top = hole->y;
+        bottom = rect->y + rect->height;
+        guac_common_rect_init(rect, left, top, right - left, bottom - top);
+
+        return 1;
+    }
+
+    /* Clip and split left */
+    else if (rect->x < hole->x) {
+        top = rect->y;
+        left = rect->x;
+        bottom = rect->y + rect->height;
+        right = hole->x;
+        guac_common_rect_init(split_rect, left, top, right - left, bottom - top);
+
+        /* Re-initialize original rect */
+        left = hole->x;
+        right = rect->x + rect->width;
+        guac_common_rect_init(rect, left, top, right - left, bottom - top);
+
+        return 1;
+    }
+
+    /* Clip and split bottom */
+    else if (rect->y + rect->height > hole->y + hole->height) {
+        top = hole->y + hole->height;
+        left = rect->x;
+        bottom = rect->y + rect->height;
+        right = rect->x + rect->width;
+        guac_common_rect_init(split_rect, left, top, right - left, bottom - top);
+
+        /* Re-initialize original rect */
+        top = rect->y;
+        bottom = hole->y + hole->height;
+        guac_common_rect_init(rect, left, top, right - left, bottom - top);
+
+        return 1;
+    }
+
+    /* Clip and split right */
+    else if (rect->x + rect->width > hole->x + hole->width) {
+        top = rect->y;
+        left = hole->x + hole->width;
+        bottom = rect->y + rect->height;
+        right = rect->x + rect->width;
+        guac_common_rect_init(split_rect, left, top, right - left, bottom - top);
+
+        /* Re-initialize original rect */
+        left = rect->x;
+        right = hole->x + hole->width;
+        guac_common_rect_init(rect, left, top, right - left, bottom - top);
+
+        return 1;
+    }
+
+    return 0;
+}

src/common/guac_rect.h

@@ -63,6 +63,27 @@ typedef struct guac_common_rect {
  */
 void guac_common_rect_init(guac_common_rect* rect, int x, int y, int width, int height);
 
+/**
+ * Expand the rectangle to fit an NxN grid.
+ *
+ * The rectangle will be shifted to the left and up, expanded and adjusted to 
+ * fit within the max bounding rect.
+ *
+ * @param cell_size
+ *     The (NxN) grid cell size.
+ *
+ * @param rect
+ *     The rectangle to adjust.
+ *
+ * @param max_rect
+ *     The bounding area in which the given rect can exist.
+ *
+ * @return
+ *     Zero on success, non-zero on error.
+ */
+int guac_common_rect_expand_to_grid(int cell_size, guac_common_rect* rect,
+                                    const guac_common_rect* max_rect);
+
 /**
  * Extend the given rect such that it contains at least the specified minimum
  * rect.
@@ -81,5 +102,45 @@ void guac_common_rect_extend(guac_common_rect* rect, const guac_common_rect* min
  */
 void guac_common_rect_constrain(guac_common_rect* rect, const guac_common_rect* max);
 
+/**
+ * Check whether a rectangle intersects another.
+ *
+ * @param rect
+ *     Rectangle to check for intersection.
+ *
+ * @param other
+ *     The other rectangle.
+ *
+ * @return
+ *     Zero if no intersection, 1 if partial intersection,
+ *     2 if first rect is completely inside the other.
+ */
+int guac_common_rect_intersects(const guac_common_rect* rect,
+                                const guac_common_rect* other);
+
+/**
+ * Clip and split a rectangle into rectangles which are not covered by the
+ * hole rectangle.
+ *
+ * This function will clip and split single edges when executed and must be
+ * invoked until it returns zero. The edges are handled counter-clockwise
+ * starting at the top edge.
+ *
+ * @param rect
+ *     The rectangle to be split. This rectangle will be clipped by the
+ *     split_rect.
+ *
+ * @param hole
+ *     The rectangle which represents the hole.
+ *
+ * @param split_rect
+ *     Resulting split rectangle.
+ *
+ * @return
+ *     Zero when no splits were done, non-zero when the rectangle was split.
+ */
+int guac_common_rect_clip_and_split(guac_common_rect* rect,
+        const guac_common_rect* hole, guac_common_rect* split_rect);
+
 #endif
 

tests/Makefile.am

@@ -40,6 +40,7 @@ test_libguac_SOURCES =           \
     common/common_suite.c        \
     common/guac_iconv.c          \
     common/guac_string.c         \
+    common/guac_rect.c           \
     protocol/suite.c             \
     protocol/base64_decode.c     \
     protocol/instruction_parse.c \

tests/common/common_suite.c

@@ -48,6 +48,7 @@ int register_common_suite() {
     if (
         CU_add_test(suite, "guac-iconv", test_guac_iconv)  == NULL
      || CU_add_test(suite, "guac-string", test_guac_string) == NULL
+     || CU_add_test(suite, "guac-rect", test_guac_rect) == NULL
        ) {
         CU_cleanup_registry();
         return CU_get_error();

tests/common/common_suite.h

@@ -49,5 +49,10 @@ void test_guac_string();
  */
 void test_guac_iconv();
 
+/**
+ * Unit test for rectangle calculation functions.
+ */
+void test_guac_rect();
+
 #endif
 

tests/common/guac_rect.c

@@ -0,0 +1,292 @@
+/*
+ * Copyright (C) 2015 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "config.h"
+
+#include "common_suite.h"
+#include "guac_rect.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <CUnit/Basic.h>
+
+void test_guac_rect() {
+
+    guac_common_rect max;
+
+    /*
+     *  Test init method
+     */
+    guac_common_rect_init(&max, 0, 0, 100, 100);
+    CU_ASSERT_EQUAL(0, max.x);
+    CU_ASSERT_EQUAL(0, max.y);
+    CU_ASSERT_EQUAL(100, max.width);
+    CU_ASSERT_EQUAL(100, max.height);
+
+    /*
+     * Test constrain method
+     */
+    guac_common_rect rect;
+    guac_common_rect_init(&rect, -10, -10, 110, 110);
+    guac_common_rect_init(&max, 0, 0, 100, 100);
+    guac_common_rect_constrain(&rect, &max);
+    CU_ASSERT_EQUAL(0, rect.x);
+    CU_ASSERT_EQUAL(0, rect.y);
+    CU_ASSERT_EQUAL(100, rect.width);
+    CU_ASSERT_EQUAL(100, rect.height);
+
+    /*
+     * Test extend method
+     */
+    guac_common_rect_init(&rect, 10, 10, 90, 90);
+    guac_common_rect_init(&max, 0, 0, 100, 100);
+    guac_common_rect_extend(&rect, &max);
+    CU_ASSERT_EQUAL(0, rect.x);
+    CU_ASSERT_EQUAL(0, rect.y);
+    CU_ASSERT_EQUAL(100, rect.width);
+    CU_ASSERT_EQUAL(100, rect.height);
+
+    /*
+     * Test adjust method
+     */
+    int cell_size = 16;
+
+    /* Simple adjustment */
+    guac_common_rect_init(&rect, 0, 0, 25, 25);
+    guac_common_rect_init(&max, 0, 0, 100, 100);
+    guac_common_rect_expand_to_grid(cell_size, &rect, &max);
+    CU_ASSERT_EQUAL(0, rect.x);
+    CU_ASSERT_EQUAL(0, rect.y);
+    CU_ASSERT_EQUAL(32, rect.width);
+    CU_ASSERT_EQUAL(32, rect.height);
+
+    /* Adjustment with moving of rect */
+    guac_common_rect_init(&rect, 75, 75, 25, 25);
+    guac_common_rect_init(&max, 0, 0, 100, 100);
+    guac_common_rect_expand_to_grid(cell_size, &rect, &max);
+    CU_ASSERT_EQUAL(max.width - 32, rect.x);
+    CU_ASSERT_EQUAL(max.height - 32, rect.y);
+    CU_ASSERT_EQUAL(32, rect.width);
+    CU_ASSERT_EQUAL(32, rect.height);
+
+    guac_common_rect_init(&rect, -5, -5, 25, 25);
+    guac_common_rect_init(&max, 0, 0, 100, 100);
+    guac_common_rect_expand_to_grid(cell_size, &rect, &max);
+    CU_ASSERT_EQUAL(0, rect.x);
+    CU_ASSERT_EQUAL(0, rect.y);
+    CU_ASSERT_EQUAL(32, rect.width);
+    CU_ASSERT_EQUAL(32, rect.height);
+
+    /* Adjustment with moving and clamping of rect */
+    guac_common_rect_init(&rect, 0, 0, 25, 15);
+    guac_common_rect_init(&max, 0, 5, 32, 15);
+    guac_common_rect_expand_to_grid(cell_size, &rect, &max);
+    CU_ASSERT_EQUAL(max.x, rect.x);
+    CU_ASSERT_EQUAL(max.y, rect.y);
+    CU_ASSERT_EQUAL(max.width, rect.width);
+    CU_ASSERT_EQUAL(max.height, rect.height);
+
+    /*
+     *  Rectangle intersection tests
+     */
+    guac_common_rect min;
+    guac_common_rect_init(&min, 10, 10, 10, 10);
+
+    /* Rectangle intersection - empty
+     * rectangle is outside */
+    guac_common_rect_init(&rect, 25, 25, 5, 5);
+    int res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(0, res);
+
+    /* Rectangle intersection - complete
+     * rectangle is completely inside */
+    guac_common_rect_init(&rect, 11, 11, 5, 5);
+    res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(2, res);
+
+    /* Rectangle intersection - partial
+     * rectangle intersects UL */
+    guac_common_rect_init(&rect, 8, 8, 5, 5);
+    res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(1, res);
+
+    /* Rectangle intersection - partial
+     * rectangle intersects LR */
+    guac_common_rect_init(&rect, 18, 18, 5, 5);
+    res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(1, res);
+
+    /* Rectangle intersection - complete
+     * rect intersects along UL but inside */
+    guac_common_rect_init(&rect, 10, 10, 5, 5);
+    res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(2, res);
+
+    /* Rectangle intersection - partial
+     * rectangle intersects along L but outside */
+    guac_common_rect_init(&rect, 5, 10, 5, 5);
+    res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(1, res);
+
+    /* Rectangle intersection - complete
+     * rectangle intersects along LR but rest is inside */
+    guac_common_rect_init(&rect, 15, 15, 5, 5);
+    res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(2, res);
+
+    /* Rectangle intersection - partial
+     * rectangle intersects along R but rest is outside */
+    guac_common_rect_init(&rect, 20, 10, 5, 5);
+    res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(1, res);
+
+    /* Rectangle intersection - partial
+     * rectangle encloses min; which is a partial intersection */
+    guac_common_rect_init(&rect, 5, 5, 20, 20);
+    res = guac_common_rect_intersects(&rect, &min);
+    CU_ASSERT_EQUAL(1, res);
+
+    /*
+     * Basic test of clip and split method
+     */
+    guac_common_rect_init(&min, 10, 10, 10, 10);
+    guac_common_rect cut;
+
+    /* Clip top */
+    guac_common_rect_init(&rect, 10, 5, 10, 10);
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(1, res);
+    CU_ASSERT_EQUAL(10, cut.x);
+    CU_ASSERT_EQUAL(5, cut.y);
+    CU_ASSERT_EQUAL(10, cut.width);
+    CU_ASSERT_EQUAL(5, cut.height);
+
+    CU_ASSERT_EQUAL(10, rect.x);
+    CU_ASSERT_EQUAL(10, rect.y);
+    CU_ASSERT_EQUAL(10, rect.width);
+    CU_ASSERT_EQUAL(5, rect.height);
+
+    /* Clip bottom */
+    guac_common_rect_init(&rect, 10, 15, 10, 10);
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(1, res);
+    CU_ASSERT_EQUAL(10, cut.x);
+    CU_ASSERT_EQUAL(20, cut.y);
+    CU_ASSERT_EQUAL(10, cut.width);
+    CU_ASSERT_EQUAL(5, cut.height);
+
+    CU_ASSERT_EQUAL(10, rect.x);
+    CU_ASSERT_EQUAL(15, rect.y);
+    CU_ASSERT_EQUAL(10, rect.width);
+    CU_ASSERT_EQUAL(5, rect.height);
+
+    /* Clip left */
+    guac_common_rect_init(&rect, 5, 10, 10, 10);
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(1, res);
+    CU_ASSERT_EQUAL(5, cut.x);
+    CU_ASSERT_EQUAL(10, cut.y);
+    CU_ASSERT_EQUAL(5, cut.width);
+    CU_ASSERT_EQUAL(10, cut.height);
+
+    CU_ASSERT_EQUAL(10, rect.x);
+    CU_ASSERT_EQUAL(10, rect.y);
+    CU_ASSERT_EQUAL(5, rect.width);
+    CU_ASSERT_EQUAL(10, rect.height);
+
+    /* Clip right */
+    guac_common_rect_init(&rect, 15, 10, 10, 10);
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(1, res);
+    CU_ASSERT_EQUAL(20, cut.x);
+    CU_ASSERT_EQUAL(10, cut.y);
+    CU_ASSERT_EQUAL(5, cut.width);
+    CU_ASSERT_EQUAL(10, cut.height);
+
+    CU_ASSERT_EQUAL(15, rect.x);
+    CU_ASSERT_EQUAL(10, rect.y);
+    CU_ASSERT_EQUAL(5, rect.width);
+    CU_ASSERT_EQUAL(10, rect.height);
+
+    /*
+     * Test a rectangle which completely covers the hole.
+     * Clip and split until done.
+     */
+    guac_common_rect_init(&rect, 5, 5, 20, 20);
+
+    /* Clip top */
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(1, res);
+    CU_ASSERT_EQUAL(5, cut.x);
+    CU_ASSERT_EQUAL(5, cut.y);
+    CU_ASSERT_EQUAL(20, cut.width);
+    CU_ASSERT_EQUAL(5, cut.height);
+
+    CU_ASSERT_EQUAL(5, rect.x);
+    CU_ASSERT_EQUAL(10, rect.y);
+    CU_ASSERT_EQUAL(20, rect.width);
+    CU_ASSERT_EQUAL(15, rect.height);
+
+    /* Clip left */
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(1, res);
+    CU_ASSERT_EQUAL(5, cut.x);
+    CU_ASSERT_EQUAL(10, cut.y);
+    CU_ASSERT_EQUAL(5, cut.width);
+    CU_ASSERT_EQUAL(15, cut.height);
+
+    CU_ASSERT_EQUAL(10, rect.x);
+    CU_ASSERT_EQUAL(10, rect.y);
+    CU_ASSERT_EQUAL(15, rect.width);
+    CU_ASSERT_EQUAL(15, rect.height);
+
+    /* Clip bottom */
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(1, res);
+    CU_ASSERT_EQUAL(10, cut.x);
+    CU_ASSERT_EQUAL(20, cut.y);
+    CU_ASSERT_EQUAL(15, cut.width);
+    CU_ASSERT_EQUAL(5, cut.height);
+
+    CU_ASSERT_EQUAL(10, rect.x);
+    CU_ASSERT_EQUAL(10, rect.y);
+    CU_ASSERT_EQUAL(15, rect.width);
+    CU_ASSERT_EQUAL(10, rect.height);
+
+    /* Clip right */
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(20, cut.x);
+    CU_ASSERT_EQUAL(10, cut.y);
+    CU_ASSERT_EQUAL(5, cut.width);
+    CU_ASSERT_EQUAL(10, cut.height);
+
+    CU_ASSERT_EQUAL(10, rect.x);
+    CU_ASSERT_EQUAL(10, rect.y);
+    CU_ASSERT_EQUAL(10, rect.width);
+    CU_ASSERT_EQUAL(10, rect.height);
+
+    /* Make sure nothing is left to do */
+    res = guac_common_rect_clip_and_split(&rect, &min, &cut);
+    CU_ASSERT_EQUAL(0, res);
+
+}
+