ref: 0579ca1005ba961cf0f1c38210d259edbb54a97b
parent: 87aec91b37fc698ae5777ff918473a46799a8f86
author: Simon Tatham <anakin@pobox.com>
date: Wed May 12 08:33:03 EDT 2004
Fiddle with the coordinate system to see if I can improve user experience. [originally from svn r4219]
--- a/rect.c
+++ b/rect.c
@@ -76,6 +76,9 @@
#define TILE_SIZE 24
#define BORDER 18
+#define CORNER_TOLERANCE 0.15F
+#define CENTRE_TOLERANCE 0.15F
+
#define FLASH_TIME 0.13F
#define COORD(x) ( (x) * TILE_SIZE + BORDER )
@@ -173,8 +176,8 @@
{if (params->w <= 0 && params->h <= 0)
return "Width and height must both be greater than zero";
- if (params->w * params->h < 4)
- return "Total area must be at least 4";
+ if (params->w < 2 && params->h < 2)
+ return "Grid area must be greater than one";
return NULL;
}
@@ -197,9 +200,13 @@
int nrects = 0, rectsize = 0;
/*
- * Maximum rectangle area is 1/6 of total grid size.
+ * Maximum rectangle area is 1/6 of total grid size, unless
+ * this means we can't place any rectangles at all in which
+ * case we set it to 2 at minimum.
*/
maxarea = params->w * params->h / 6;
+ if (maxarea < 2)
+ maxarea = 2;
for (rw = 1; rw <= params->w; rw++)
for (rh = 1; rh <= params->h; rh++) {@@ -910,29 +917,88 @@
sfree(ui);
}
-int coord_round(float coord)
+void coord_round(float x, float y, int *xr, int *yr)
{- int i;
- float dist;
+ float xs, ys, xv, yv, dx, dy, dist;
/*
- * Find the nearest integer.
+ * Find the nearest square-centre.
*/
- i = (int)(coord + 0.5F);
+ xs = (float)floor(x) + 0.5F;
+ ys = (float)floor(y) + 0.5F;
/*
- * Find the distance from us to that integer.
+ * And find the nearest grid vertex.
*/
- dist = (float)fabs(coord - (float)i);
+ xv = (float)floor(x + 0.5F);
+ yv = (float)floor(y + 0.5F);
/*
- * If we're within the tolerance limit, return the edge
- * coordinate. Otherwise, return the centre coordinate.
+ * We allocate clicks in parts of the grid square to either
+ * corners, edges or square centres, as follows:
+ *
+ * +--+--------+--+
+ * | | | |
+ * +--+ +--+
+ * | `. ,' |
+ * | +--+ |
+ * | | | |
+ * | +--+ |
+ * | ,' `. |
+ * +--+ +--+
+ * | | | |
+ * +--+--------+--+
+ *
+ * (Not to scale!)
+ *
+ * In other words: we measure the square distance (i.e.
+ * max(dx,dy)) from the click to the nearest corner, and if
+ * it's within CORNER_TOLERANCE then we return a corner click.
+ * We measure the square distance from the click to the nearest
+ * centre, and if that's within CENTRE_TOLERANCE we return a
+ * centre click. Failing that, we find which of the two edge
+ * centres is nearer to the click and return that edge.
*/
- if (dist < 0.3F)
- return i * 2;
- else
- return 1 + 2 * (int)coord;
+
+ /*
+ * Check for corner click.
+ */
+ dx = (float)fabs(x - xv);
+ dy = (float)fabs(y - yv);
+ dist = (dx > dy ? dx : dy);
+ if (dist < CORNER_TOLERANCE) {+ *xr = 2 * (int)xv;
+ *yr = 2 * (int)yv;
+ } else {+ /*
+ * Check for centre click.
+ */
+ dx = (float)fabs(x - xs);
+ dy = (float)fabs(y - ys);
+ dist = (dx > dy ? dx : dy);
+ if (dist < CENTRE_TOLERANCE) {+ *xr = 1 + 2 * (int)xs;
+ *yr = 1 + 2 * (int)ys;
+ } else {+ /*
+ * Failing both of those, see which edge we're closer to.
+ * Conveniently, this is simply done by testing the relative
+ * magnitude of dx and dy (which are currently distances from
+ * the square centre).
+ */
+ if (dx > dy) {+ /* Vertical edge: x-coord of corner,
+ * y-coord of square centre. */
+ *xr = 2 * (int)xv;
+ *yr = 1 + 2 * (int)ys;
+ } else {+ /* Horizontal edge: x-coord of square centre,
+ * y-coord of corner. */
+ *xr = 1 + 2 * (int)xs;
+ *yr = 2 * (int)yv;
+ }
+ }
+ }
}
static void ui_draw_rect(game_state *state, game_ui *ui,
@@ -996,8 +1062,7 @@
return NULL;
}
- xc = coord_round(FROMCOORD((float)x));
- yc = coord_round(FROMCOORD((float)y));
+ coord_round(FROMCOORD((float)x), FROMCOORD((float)y), &xc, &yc);
if (startdrag) {ui->drag_start_x = xc;
@@ -1043,7 +1108,7 @@
* We've made a real change to the grid. Check to see
* if the game has been completed.
*/
- if (!ret->completed) {+ if (ret && !ret->completed) {int x, y, ok;
unsigned char *correct = get_correct(ret);