| Re: [AD] new GUI focus selection algorithm |
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> For example my program which made me think about the focusing at all:
>
> Start
> Fullscreen
> End
>
> It will go up from Start to End, or down from End to Start, with the
> wrapping. With just a penalty, it will jump to Fullscreen in both cases.
> (The original code had negative distances, that's why it could just add
> 0x10000 to achieve the wrapping.)
Ok, I have just totally overlooked the wrapping requirement until now :-)
And thinking a bit more about it, I now understand your proposition to use
the actual dimensions of the screen rather than the somewhat arbitrary
current wrapping value.
Revised patch attached.
--
Eric Botcazou
--- /home/eric/cvs/allegro/src/gui.c Sat Nov 29 08:25:22 2003
+++ allegro/src/gui.c Sun Nov 30 09:58:45 2003
@@ -18,6 +18,8 @@
*
* Eric Botcazou added the support for non-blocking menus.
*
+ * Elias Pschernig and Sven Sandberg improved the focus algorithm.
+ *
* See readme.txt for copyright information.
*/
@@ -506,6 +508,16 @@ typedef struct OBJ_LIST
} OBJ_LIST;
+/* Weight ratio between the orthogonal direction and the main direction
+ when calculating the distance for the focus algorithm. */
+#define DISTANCE_RATIO 8
+
+/* Maximum size (in bytes) of a dialog array. */
+#define MAX_SIZE 0x10000 /* 64 kb */
+
+enum axis { X_AXIS, Y_AXIS };
+
+
/* obj_list_cmp:
* Callback function for qsort().
@@ -524,8 +536,9 @@ static int cmp_tab(AL_CONST DIALOG *d1,
{
int ret = (int)((AL_CONST unsigned long)d2 - (AL_CONST unsigned long)d1);
+ /* Wrap around if d2 is before d1 in the dialog array. */
if (ret < 0)
- ret += 0x10000;
+ ret += MAX_SIZE;
return ret;
}
@@ -539,25 +552,83 @@ static int cmp_shift_tab(AL_CONST DIALOG
{
int ret = (int)((AL_CONST unsigned long)d1 - (AL_CONST unsigned long)d2);
+ /* Wrap around if d2 is after d1 in the dialog array. */
if (ret < 0)
- ret += 0x10000;
+ ret += MAX_SIZE;
return ret;
}
+/* min_dist:
+ * Returns the minimum distance between dialogs 'd1' and 'd2'. 'main_axis'
+ * is taken account to give different weights to the axes in the distance
+ * formula, as well as to shift the actual position of 'd2' along the axis
+ * by the amount specified by 'bias'.
+ */
+static int min_dist(AL_CONST DIALOG *d1, AL_CONST DIALOG *d2, enum axis main_axis, int bias)
+{
+ int x_left = d1->x - d2->x - d2->w + 1;
+ int x_right = d2->x - d1->x - d1->w + 1;
+ int y_top = d1->y - d2->y - d2->h + 1;
+ int y_bottom = d2->y - d1->y - d1->h + 1;
+
+ if (main_axis == X_AXIS) {
+ x_left -= bias;
+ x_right += bias;
+ y_top *= DISTANCE_RATIO;
+ y_bottom *= DISTANCE_RATIO;
+ }
+ else {
+ x_left *= DISTANCE_RATIO;
+ x_right *= DISTANCE_RATIO;
+ y_top -= bias;
+ y_bottom += bias;
+ }
+
+ if (x_left > 0) { /* d2 is left of d1 */
+ if (y_top > 0) /* d2 is above d1 */
+ return x_left + y_top;
+ else if (y_bottom > 0) /* d2 is below d1 */
+ return x_left + y_bottom;
+ else /* vertically overlapping */
+ return x_left;
+ }
+ else if (x_right > 0) { /* d2 is right of d1 */
+ if (y_top > 0) /* d2 is above d1 */
+ return x_right + y_top;
+ else if (y_bottom > 0) /* d2 is below d1 */
+ return x_right + y_bottom;
+ else /* vertically overlapping */
+ return x_right;
+ }
+ /* horizontally overlapping */
+ else if (y_top > 0) /* d2 is above d1 */
+ return y_top;
+ else if (y_bottom > 0) /* d2 is below d1 */
+ return y_bottom;
+ else /* overlapping */
+ return 0;
+}
+
+
+
/* cmp_right:
* Comparison function for right arrow key movement.
*/
static int cmp_right(AL_CONST DIALOG *d1, AL_CONST DIALOG *d2)
{
- int ret = (d2->x - d1->x) + ABS(d1->y - d2->y) * 8;
+ int bias;
- if (d1->x >= d2->x)
- ret += 0x10000;
+ /* Wrap around if d2 is not fully contained in the half-plan
+ delimited by d1's right edge and not containing it. */
+ if (d2->x < d1->x + d1->w)
+ bias = +SCREEN_W;
+ else
+ bias = 0;
- return ret;
+ return min_dist(d1, d2, X_AXIS, bias);
}
@@ -567,12 +638,16 @@ static int cmp_right(AL_CONST DIALOG *d1
*/
static int cmp_left(AL_CONST DIALOG *d1, AL_CONST DIALOG *d2)
{
- int ret = (d1->x - d2->x) + ABS(d1->y - d2->y) * 8;
+ int bias;
- if (d1->x <= d2->x)
- ret += 0x10000;
+ /* Wrap around if d2 is not fully contained in the half-plan
+ delimited by d1's left edge and not containing it. */
+ if (d2->x + d2->w > d1->x)
+ bias = -SCREEN_W;
+ else
+ bias = 0;
- return ret;
+ return min_dist(d1, d2, X_AXIS, bias);
}
@@ -582,12 +657,16 @@ static int cmp_left(AL_CONST DIALOG *d1,
*/
static int cmp_down(AL_CONST DIALOG *d1, AL_CONST DIALOG *d2)
{
- int ret = (d2->y - d1->y) + ABS(d1->x - d2->x) * 8;
+ int bias;
- if (d1->y >= d2->y)
- ret += 0x10000;
+ /* Wrap around if d2 is not fully contained in the half-plan
+ delimited by d1's bottom edge and not containing it. */
+ if (d2->y < d1->y + d1->h)
+ bias = +SCREEN_H;
+ else
+ bias = 0;
- return ret;
+ return min_dist(d1, d2, Y_AXIS, bias);
}
@@ -597,12 +676,16 @@ static int cmp_down(AL_CONST DIALOG *d1,
*/
static int cmp_up(AL_CONST DIALOG *d1, AL_CONST DIALOG *d2)
{
- int ret = (d1->y - d2->y) + ABS(d1->x - d2->x) * 8;
+ int bias;
- if (d1->y <= d2->y)
- ret += 0x10000;
+ /* Wrap around if d2 is not fully contained in the half-plan
+ delimited by d1's top edge and not containing it. */
+ if (d2->y + d2->h > d1->y)
+ bias = -SCREEN_H;
+ else
+ bias = 0;
- return ret;
+ return min_dist(d1, d2, Y_AXIS, bias);
}
@@ -631,7 +714,8 @@ static int move_focus(DIALOG *d, int asc
/* fill temporary table */
for (c=0; d[c].proc; c++) {
- if ((*focus_obj < 0) || (c != *focus_obj)) {
+ if (((*focus_obj < 0) || (c != *focus_obj))
+ && !(d[c].flags & (D_DISABLED | D_HIDDEN))) {
obj[obj_count].index = c;
if (*focus_obj >= 0)
obj[obj_count].diff = cmp(d+*focus_obj, d+c);