ref: e45cd43aaab7af014607b2578ec68a5bbec1b609
parent: fba22f04d684dfb14d1f74c12ba71dd0b2f7be32
author: Ben Harris <[email protected]>
date: Mon Nov 7 16:42:38 EST 2022
Teach the mid-end about device pixel ratios The device pixel ratio indicates how many physical pixels there are in the platonic ideal of a pixel, at least approximately. In Web browsers, the device pixel ratio is used to represent "retina" displays with particularly high pixel densities, and also to reflect user-driven zooming of the page to different text sizes. The mid-end uses the device pixel ratio to adjust the tile size at startup, and can also respond to changes in device pixel ratio by adjusting the time size later. This is accomplished through a new argument to midend_size() which can simply be passed as 1.0 in any front end that doesn't care about this.
--- a/devel.but
+++ b/devel.but
@@ -2972,7 +2972,7 @@
\H{midend-size} \cw{midend_size()}-\c void midend_size(midend *me, int *x, int *y, bool user_size);
+\c void midend_size(midend *me, int *x, int *y, bool user_size, double device_pixel_ratio);
Tells the mid-end to figure out its window size.
@@ -3028,6 +3028,24 @@
to use scroll bars for large puzzles), you can pass dimensions of
\cw{INT_MAX} as input to this function. You should probably not do that \e{and} set the \c{user_size} flag, though!+
+The \cw{device_pixel_ratio} allows the front end to specify that its+pixels are unusually large or small (or should be treated as such).
+The mid-end uses this to adjust the tile size, both at startup (if the
+ratio is not 1) and if the ratio changes.
+
+A \cw{device_pixel_ratio} of 1 indicates normal-sized pixels.+\q{Normal} is not precisely defined, but it's about 4 pixels per+millimetre on a screen designed to be viewed from a metre away, or a
+size such that text 15 pixels high is comfortably readable. Some
+platforms have a concept of a logical pixel that this can be mapped
+onto. For instance, Cascading Style Sheets (CSS) has a unit called
+\cq{px} that only matches physical pixels at a \cw{device_pixel_ratio}+of 1.
+
+The \cw{device_pixel_ratio} indicates the number of physical pixels in+a normal-sized pixel, so values less than 1 indicate unusually large
+pixels and values greater than 1 indicate unusually small pixels.
The midend relies on the frontend calling \cw{midend_new_game()} (\k{midend-new-game}) before calling \cw{midend_size()}.--- a/emcc.c
+++ b/emcc.c
@@ -195,7 +195,7 @@
int w, h;
double dpr;
w = h = INT_MAX;
- midend_size(me, &w, &h, false);
+ midend_size(me, &w, &h, false, 1.0);
if (initial) {dpr = js_get_device_pixel_ratio();
if (dpr != 1.0) {@@ -207,7 +207,7 @@
*/
w *= dpr;
h *= dpr;
- midend_size(me, &w, &h, true);
+ midend_size(me, &w, &h, true, 1.0);
}
}
js_canvas_set_size(w, h);
@@ -219,7 +219,7 @@
/* Called from JS when the device pixel ratio changes */
void rescale_puzzle(int w, int h)
{- midend_size(me, &w, &h, true);
+ midend_size(me, &w, &h, true, 1.0);
if (canvas_w != w || canvas_h != h) { js_canvas_set_size(w, h);
canvas_w = w;
--- a/gtk.c
+++ b/gtk.c
@@ -1674,7 +1674,7 @@
fe->w = x;
fe->h = y;
- midend_size(fe->me, &x, &y, true);
+ midend_size(fe->me, &x, &y, true, 1.0);
fe->pw = x;
fe->ph = y;
#if GTK_CHECK_VERSION(3,10,0)
@@ -2210,7 +2210,7 @@
*/
x = INT_MAX;
y = INT_MAX;
- midend_size(fe->me, &x, &y, false);
+ midend_size(fe->me, &x, &y, false, 1.0);
*px = x;
*py = y;
}
--- a/midend.c
+++ b/midend.c
@@ -89,7 +89,8 @@
int pressed_mouse_button;
- int preferred_tilesize, tilesize, winwidth, winheight;
+ int preferred_tilesize, preferred_tilesize_dpr, tilesize;
+ int winwidth, winheight;
void (*game_id_change_notify_function)(void *);
void *game_id_change_notify_ctx;
@@ -130,11 +131,14 @@
void midend_reset_tilesize(midend *me)
{me->preferred_tilesize = me->ourgame->preferred_tilesize;
+ me->preferred_tilesize_dpr = 1.0;
{/*
* Allow an environment-based override for the default tile
* size by defining a variable along the lines of
* `NET_TILESIZE=15'.
+ *
+ * XXX How should this interact with DPR?
*/
char buf[80], *e;
@@ -306,10 +310,50 @@
}
}
-void midend_size(midend *me, int *x, int *y, bool user_size)
+/*
+ * There is no one correct way to convert tilesizes between device
+ * pixel ratios, because there's only a loosely-defined relationship
+ * between tilesize and the actual size of a puzzle. We define this
+ * function as the canonical conversion function so everything in the
+ * midend will be consistent.
+ */
+static int convert_tilesize(midend *me, int old_tilesize,
+ double old_dpr, double new_dpr)
{+ int x, y, rx, ry, min, max, mid;
+ game_params *defaults = me->ourgame->default_params();
+
+ if (new_dpr == old_dpr)
+ return old_tilesize;
+ me->ourgame->compute_size(defaults, old_tilesize, &x, &y);
+ x *= new_dpr / old_dpr;
+ y *= new_dpr / old_dpr;
+
+ min = max = 1;
+ do {+ max *= 2;
+ me->ourgame->compute_size(defaults, max, &rx, &ry);
+ } while (rx <= x && ry <= y);
+
+ while (max - min > 1) {+ int mid = (max + min) / 2;
+ me->ourgame->compute_size(defaults, mid, &rx, &ry);
+ if (rx <= x && ry <= y)
+ min = mid;
+ else
+ max = mid;
+ }
+
+ me->ourgame->free_params(defaults);
+ return min;
+}
+
+void midend_size(midend *me, int *x, int *y, bool user_size,
+ double device_pixel_ratio)
+{int min, max;
int rx, ry;
+ int preferred_tilesize;
/*
* We can't set the size on the same drawstate twice. So if
@@ -339,7 +383,9 @@
me->ourgame->compute_size(me->params, max, &rx, &ry);
} while (rx <= *x && ry <= *y);
} else
- max = me->preferred_tilesize + 1;
+ max = convert_tilesize(me, me->preferred_tilesize,
+ me->preferred_tilesize_dpr,
+ device_pixel_ratio) + 1;
min = 1;
/*
@@ -362,9 +408,11 @@
*/
me->tilesize = min;
- if (user_size)
+ if (user_size) {/* If the user requested a change in size, make it permanent. */
me->preferred_tilesize = me->tilesize;
+ me->preferred_tilesize_dpr = device_pixel_ratio;
+ }
midend_size_new_drawstate(me);
*x = me->winwidth;
*y = me->winheight;
--- a/nestedvm.c
+++ b/nestedvm.c
@@ -217,7 +217,7 @@
int x, y;
x = width;
y = height;
- midend_size(fe->me, &x, &y, true);
+ midend_size(fe->me, &x, &y, true, 1.0);
fe->ox = (width - x) / 2;
fe->oy = (height - y) / 2;
fe->w = x;
@@ -358,7 +358,7 @@
x = INT_MAX;
y = INT_MAX;
- midend_size(fe->me, &x, &y, false);
+ midend_size(fe->me, &x, &y, false, 1.0);
_call_java(3, x, y, 0);
}
--- a/osx.m
+++ b/osx.m
@@ -524,7 +524,7 @@
frame.origin.x = 0;
w = h = INT_MAX;
- midend_size(me, &w, &h, false);
+ midend_size(me, &w, &h, false, 1.0);
frame.size.width = w;
frame.size.height = h;
fe.w = w;
@@ -559,7 +559,7 @@
*/
midend_new_game(me);
w = h = INT_MAX;
- midend_size(me, &w, &h, false);
+ midend_size(me, &w, &h, false, 1.0);
rect.size.width = w;
rect.size.height = h;
fe.w = w;
@@ -959,7 +959,7 @@
int w, h;
w = h = INT_MAX;
- midend_size(me, &w, &h, false);
+ midend_size(me, &w, &h, false, 1.0);
size.width = w;
size.height = h;
fe.w = w;
--- a/puzzles.h
+++ b/puzzles.h
@@ -299,7 +299,8 @@
const game *midend_which_game(midend *me);
void midend_set_params(midend *me, game_params *params);
game_params *midend_get_params(midend *me);
-void midend_size(midend *me, int *x, int *y, bool user_size);
+void midend_size(midend *me, int *x, int *y, bool user_size,
+ double device_pixel_ratio);
void midend_reset_tilesize(midend *me);
void midend_new_game(midend *me);
void midend_restart_game(midend *me);
--- a/windows.c
+++ b/windows.c
@@ -1285,7 +1285,7 @@
* See if we actually got the window size we wanted, and adjust
* the puzzle size if not.
*/
- midend_size(fe->me, &x, &y, true);
+ midend_size(fe->me, &x, &y, true, 1.0);
if (x != cx || y != cy) {/*
* Resize the window, now we know what size we _really_
@@ -1611,7 +1611,7 @@
fe->statusbar = NULL;
get_max_puzzle_size(fe, &x, &y);
- midend_size(fe->me, &x, &y, false);
+ midend_size(fe->me, &x, &y, false, 1.0);
r.left = r.top = 0;
r.right = x;
@@ -2374,12 +2374,12 @@
int x, y;
get_max_puzzle_size(fe, &x, &y);
- midend_size(fe->me, &x, &y, false);
+ midend_size(fe->me, &x, &y, false, 1.0);
if (scale != 1.0) {x = (int)((float)x * fe->puzz_scale);
y = (int)((float)y * fe->puzz_scale);
- midend_size(fe->me, &x, &y, true);
+ midend_size(fe->me, &x, &y, true, 1.0);
}
fe->ymin = (fe->xmin * y) / x;