mirror of
https://github.com/subsurface/subsurface.git
synced 2024-11-28 05:00:20 +00:00
Fix up horribly broken cairo scaling
The way cairo does scaling is really really inconvenient, and one of the things in cairo that is fundamentally mis-designed. Cairo scaling always affects both coordinates and object sizes, and the two can apparently never be split apart. Which is very much not what we want: we want just coordinate scaling. So we cannot use 'cairo_scale()' to scale our canvas, because that screws up lines and text size too. And no, you cannot "fix" that by de-scaling the line size etc - because line size is one-dimensional, so you can't undo the (different) scaling in X/Y. Sad. I realize that often you do want to scale object size with coordinate transformation, but quite often you *don't* want to. Yeah, we could do random context save/restore in odd places etc, but that's just a sign of the bad design of cairo scaling. Work around it by introducing our own graphics context with scaling, which does it right. I don't like this, but it seems to be better than the alternatives. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds
parent
96f5bea1ac
commit
d4a1dfb3d9
1 changed files with 120 additions and 95 deletions
215
profile.c
215
profile.c
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@ -9,6 +9,33 @@
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int selected_dive = 0;
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/*
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* Cairo scaling really is horribly horribly mis-designed.
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*
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* Which is sad, because I really like Cairo otherwise. But
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* the fact that the line width is scaled with the same scale
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* as the coordinate system is a f*&%ing disaster. So we
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* can't use it, and instead have this butt-ugly wrapper thing..
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*/
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struct graphics_context {
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cairo_t *cr;
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double maxx, maxy;
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double scalex, scaley;
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};
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/* Scale to 0,0 -> maxx,maxy */
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#define SCALE(gc,x,y) (x)*gc->maxx/gc->scalex,(y)*gc->maxy/gc->scaley
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static void move_to(struct graphics_context *gc, double x, double y)
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{
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cairo_move_to(gc->cr, SCALE(gc, x, y));
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}
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static void line_to(struct graphics_context *gc, double x, double y)
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{
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cairo_line_to(gc->cr, SCALE(gc, x, y));
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}
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#define ROUND_UP(x,y) ((((x)+(y)-1)/(y))*(y))
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/*
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@ -34,10 +61,12 @@ typedef struct {
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enum {CENTER,LEFT} allign;
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} text_render_options_t;
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static void plot_text(cairo_t *cr, text_render_options_t *tro,
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static void plot_text(struct graphics_context *gc, text_render_options_t *tro,
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double x, double y, const char *fmt, ...)
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{
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cairo_t *cr = gc->cr;
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cairo_text_extents_t extents;
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double dx, dy;
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char buffer[80];
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va_list args;
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@ -46,17 +75,21 @@ static void plot_text(cairo_t *cr, text_render_options_t *tro,
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va_end(args);
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cairo_text_extents(cr, buffer, &extents);
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dx = 0;
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if (tro->allign == CENTER)
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x -= extents.width/2 + extents.x_bearing;
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y += extents.height * 1.2;
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dx = -(extents.width/2 + extents.x_bearing);
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dy = extents.height * 1.2;
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move_to(gc, x, y);
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cairo_rel_move_to(cr, dx, dy);
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cairo_move_to(cr, x, y);
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cairo_text_path(cr, buffer);
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cairo_set_source_rgb(cr, 0, 0, 0);
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cairo_stroke(cr);
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cairo_move_to(cr, x, y);
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move_to(gc, x, y);
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cairo_rel_move_to(cr, dx, dy);
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cairo_set_source_rgb(cr, tro->r, tro->g, tro->b);
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cairo_show_text(cr, buffer);
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}
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@ -113,12 +146,7 @@ static struct sample *next_minmax(struct sample *sample, struct sample *end, int
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return result;
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}
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/* Scale to 0,0 -> maxx,maxy */
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#define SCALE(x,y) (x)*maxx/scalex,(y)*maxy/scaley
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void plot_text_samples(struct dive *dive, cairo_t *cr,
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double maxx, double maxy,
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double scalex, double scaley,
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void plot_text_samples(struct dive *dive, struct graphics_context *gc,
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struct sample *a, struct sample *b)
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{
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struct sample *max, *min;
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@ -137,12 +165,12 @@ void plot_text_samples(struct dive *dive, cairo_t *cr,
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double d;
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min = next_minmax(max, b, 0);
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plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, a, max);
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plot_text_samples(dive, gc, a, max);
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if (min) {
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plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, max, min);
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plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, min, b);
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plot_text_samples(dive, gc, max, min);
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plot_text_samples(dive, gc, min, b);
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} else
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plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, max, b);
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plot_text_samples(dive, gc, max, b);
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switch (output_units.length) {
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case METERS:
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@ -155,27 +183,24 @@ void plot_text_samples(struct dive *dive, cairo_t *cr,
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break;
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}
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plot_text(cr, &tro, SCALE(sec, depth.mm), fmt, d);
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plot_text(gc, &tro, sec, depth.mm, fmt, d);
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return;
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}
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}
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static void plot_depth_text(struct dive *dive, cairo_t *cr,
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double maxx, double maxy)
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static void plot_depth_text(struct dive *dive, struct graphics_context *gc)
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{
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struct sample *sample, *end;
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double scalex, scaley;
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int maxtime, maxdepth;
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/* Get plot scaling limits */
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maxtime = round_seconds_up(dive->duration.seconds);
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maxdepth = round_depth_up(dive->maxdepth);
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scalex = maxtime;
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scaley = maxdepth;
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gc->scalex = maxtime;
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gc->scaley = maxdepth;
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cairo_set_font_size(cr, 14);
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cairo_set_source_rgb(cr, 1, 0.2, 0.2);
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cairo_set_font_size(gc->cr, 14);
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/*
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* We never take the last sample into account.
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@ -185,13 +210,12 @@ static void plot_depth_text(struct dive *dive, cairo_t *cr,
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sample = dive->sample;
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end = dive->sample + dive->samples - 1;
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plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, sample, end);
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plot_text_samples(dive, gc, sample, end);
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}
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static void plot_depth_profile(struct dive *dive, cairo_t *cr,
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double maxx, double maxy)
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static void plot_depth_profile(struct dive *dive, struct graphics_context *gc)
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{
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double scalex, scaley;
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cairo_t *cr = gc->cr;
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int begins, sec, depth;
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int i, samples;
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struct sample *sample;
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@ -201,23 +225,23 @@ static void plot_depth_profile(struct dive *dive, cairo_t *cr,
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if (!samples)
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return;
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cairo_set_line_width(cr, 2);
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cairo_set_line_width(gc->cr, 2);
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/* Get plot scaling limits */
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maxtime = round_seconds_up(dive->duration.seconds);
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maxdepth = round_depth_up(dive->maxdepth);
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/* Time markers: every 5 min */
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scalex = maxtime;
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scaley = 1.0;
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gc->scalex = maxtime;
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gc->scaley = 1.0;
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for (i = 5*60; i < maxtime; i += 5*60) {
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cairo_move_to(cr, SCALE(i, 0));
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cairo_line_to(cr, SCALE(i, 1));
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move_to(gc, i, 0);
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line_to(gc, i, 1);
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}
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/* Depth markers: every 30 ft or 10 m*/
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scalex = 1.0;
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scaley = maxdepth;
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gc->scalex = 1.0;
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gc->scaley = maxdepth;
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switch (output_units.length) {
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case METERS: marker = 10000; break;
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case FEET: marker = 9144; break; /* 30 ft */
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@ -225,34 +249,34 @@ static void plot_depth_profile(struct dive *dive, cairo_t *cr,
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cairo_set_source_rgba(cr, 1, 1, 1, 0.5);
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for (i = marker; i < maxdepth; i += marker) {
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cairo_move_to(cr, SCALE(0, i));
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cairo_line_to(cr, SCALE(1, i));
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move_to(gc, 0, i);
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line_to(gc, 1, i);
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}
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cairo_stroke(cr);
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/* Show mean depth */
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cairo_set_source_rgba(cr, 1, 0.2, 0.2, 0.40);
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cairo_move_to(cr, SCALE(0, dive->meandepth.mm));
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cairo_line_to(cr, SCALE(1, dive->meandepth.mm));
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move_to(gc, 0, dive->meandepth.mm);
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line_to(gc, 1, dive->meandepth.mm);
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cairo_stroke(cr);
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scalex = maxtime;
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gc->scalex = maxtime;
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sample = dive->sample;
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cairo_set_source_rgba(cr, 1, 0.2, 0.2, 0.80);
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begins = sample->time.seconds;
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cairo_move_to(cr, SCALE(sample->time.seconds, sample->depth.mm));
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move_to(gc, sample->time.seconds, sample->depth.mm);
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for (i = 1; i < dive->samples; i++) {
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sample++;
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sec = sample->time.seconds;
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if (sec <= maxtime) {
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depth = sample->depth.mm;
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cairo_line_to(cr, SCALE(sec, depth));
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line_to(gc, sec, depth);
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}
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}
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scaley = 1.0;
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cairo_line_to(cr, SCALE(MIN(sec,maxtime), 0));
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cairo_line_to(cr, SCALE(begins, 0));
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gc->scaley = 1.0;
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line_to(gc, MIN(sec,maxtime), 0);
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line_to(gc, begins, 0);
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cairo_close_path(cr);
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cairo_set_source_rgba(cr, 1, 0.2, 0.2, 0.20);
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cairo_fill_preserve(cr);
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@ -261,13 +285,13 @@ static void plot_depth_profile(struct dive *dive, cairo_t *cr,
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}
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/* gets both the actual start and end pressure as well as the scaling factors */
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static int get_cylinder_pressure_range(struct dive *dive, double *scalex, double *scaley,
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pressure_t *startp, pressure_t *endp)
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static int get_cylinder_pressure_range(struct dive *dive, struct graphics_context *gc,
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pressure_t *startp, pressure_t *endp)
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{
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int i;
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int min, max;
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*scalex = round_seconds_up(dive->duration.seconds);
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gc->scalex = round_seconds_up(dive->duration.seconds);
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max = 0;
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min = 5000000;
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@ -295,22 +319,20 @@ static int get_cylinder_pressure_range(struct dive *dive, double *scalex, double
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endp->mbar = min;
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if (!max)
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return 0;
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*scaley = max * 1.5;
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gc->scaley = max * 1.5;
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return 1;
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}
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static void plot_cylinder_pressure(struct dive *dive, cairo_t *cr,
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double maxx, double maxy)
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static void plot_cylinder_pressure(struct dive *dive, struct graphics_context *gc)
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{
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int i, sec = -1;
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double scalex, scaley;
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if (!get_cylinder_pressure_range(dive, &scalex, &scaley, NULL, NULL))
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if (!get_cylinder_pressure_range(dive, gc, NULL, NULL))
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return;
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cairo_set_source_rgba(cr, 0.2, 1.0, 0.2, 0.80);
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cairo_set_source_rgba(gc->cr, 0.2, 1.0, 0.2, 0.80);
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cairo_move_to(cr, SCALE(0, dive->cylinder[0].start.mbar));
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move_to(gc, 0, dive->cylinder[0].start.mbar);
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for (i = 1; i < dive->samples; i++) {
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int mbar;
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struct sample *sample = dive->sample + i;
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@ -320,15 +342,15 @@ static void plot_cylinder_pressure(struct dive *dive, cairo_t *cr,
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continue;
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sec = sample->time.seconds;
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if (sec <= dive->duration.seconds)
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cairo_line_to(cr, SCALE(sec, mbar));
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line_to(gc, sec, mbar);
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}
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/*
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* We may have "surface time" events, in which case we don't go
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* back to dive duration
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*/
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if (sec < dive->duration.seconds)
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cairo_line_to(cr, SCALE(dive->duration.seconds, dive->cylinder[0].end.mbar));
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cairo_stroke(cr);
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line_to(gc, dive->duration.seconds, dive->cylinder[0].end.mbar);
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cairo_stroke(gc->cr);
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}
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/*
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@ -355,8 +377,7 @@ static double calculate_airuse(struct dive *dive)
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return airuse;
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}
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static void plot_info(struct dive *dive, cairo_t *cr,
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double maxx, double maxy)
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static void plot_info(struct dive *dive, struct graphics_context *gc)
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{
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text_render_options_t tro = {0.2, 1.0, 0.2, LEFT};
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const double liters_per_cuft = 28.317;
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@ -377,24 +398,21 @@ static void plot_info(struct dive *dive, cairo_t *cr,
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airuse /= liters_per_cuft;
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break;
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}
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plot_text(cr, &tro, maxx*0.8, maxy*0.8, "vol: %4.2f %s", airuse, unit);
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plot_text(gc, &tro, 0.8, 0.8, "vol: %4.2f %s", airuse, unit);
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if (dive->duration.seconds) {
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double pressure = 1 + (dive->meandepth.mm / 10000.0);
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double sac = airuse / pressure * 60 / dive->duration.seconds;
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plot_text(cr, &tro, maxx*0.8, maxy*0.85, "SAC: %4.2f %s/min", sac, unit);
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plot_text(gc, &tro, 0.8, 0.85, "SAC: %4.2f %s/min", sac, unit);
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}
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}
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static void plot_cylinder_pressure_text(struct dive *dive, cairo_t *cr,
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double maxx, double maxy)
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static void plot_cylinder_pressure_text(struct dive *dive, struct graphics_context *gc)
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{
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double scalex, scaley;
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pressure_t startp, endp;
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cairo_set_font_size(cr, 10);
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cairo_set_font_size(gc->cr, 10);
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if (get_cylinder_pressure_range(dive, &scalex, &scaley,
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&startp, &endp)) {
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if (get_cylinder_pressure_range(dive, gc, &startp, &endp)) {
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int start, end;
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const char *unit = "bar";
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@ -417,65 +435,72 @@ static void plot_cylinder_pressure_text(struct dive *dive, cairo_t *cr,
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}
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text_render_options_t tro = {0.2, 1.0, 0.2, LEFT};
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plot_text(cr, &tro, SCALE(0, startp.mbar), "%d %s", start, unit);
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plot_text(cr, &tro, SCALE(dive->duration.seconds, endp.mbar),
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plot_text(gc, &tro, 0, startp.mbar, "%d %s", start, unit);
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plot_text(gc, &tro, dive->duration.seconds, endp.mbar,
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"%d %s", end, unit);
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}
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}
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static void plot(cairo_t *cr, int w, int h, struct dive *dive)
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static void plot(struct graphics_context *gc, int w, int h, struct dive *dive)
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{
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double topx, topy, maxx, maxy;
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double scalex, scaley;
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double topx, topy;
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topx = w / 20.0;
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topy = h / 20.0;
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maxx = (w - 2*topx);
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maxy = (h - 2*topy);
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cairo_translate(cr, topx, topy);
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cairo_translate(gc->cr, topx, topy);
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/*
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* We can use "cairo_translate()" because that doesn't
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* scale line width etc. But the actual scaling we need
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* do set up ourselves..
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*
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* Snif. What a pity.
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*/
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gc->maxx = (w - 2*topx);
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gc->maxy = (h - 2*topy);
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/* Cylinder pressure plot */
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plot_cylinder_pressure(dive, cr, maxx, maxy);
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plot_cylinder_pressure(dive, gc);
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/* Depth profile */
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plot_depth_profile(dive, cr, maxx, maxy);
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plot_depth_profile(dive, gc);
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/* Text on top of all graphs.. */
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plot_depth_text(dive, cr, maxx, maxy);
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plot_cylinder_pressure_text(dive, cr, maxx, maxy);
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plot_depth_text(dive, gc);
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plot_cylinder_pressure_text(dive, gc);
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/* And info box in the lower right corner.. */
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plot_info(dive, cr, maxx, maxy);
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gc->scalex = gc->scaley = 1.0;
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plot_info(dive, gc);
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/* Bounding box last */
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scalex = scaley = 1.0;
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cairo_set_source_rgb(cr, 1, 1, 1);
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cairo_move_to(cr, SCALE(0,0));
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cairo_line_to(cr, SCALE(0,1));
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cairo_line_to(cr, SCALE(1,1));
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cairo_line_to(cr, SCALE(1,0));
|
||||
cairo_close_path(cr);
|
||||
cairo_stroke(cr);
|
||||
cairo_set_source_rgb(gc->cr, 1, 1, 1);
|
||||
move_to(gc, 0, 0);
|
||||
line_to(gc, 0, 1);
|
||||
line_to(gc, 1, 1);
|
||||
line_to(gc, 1, 0);
|
||||
cairo_close_path(gc->cr);
|
||||
cairo_stroke(gc->cr);
|
||||
|
||||
}
|
||||
|
||||
static gboolean expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer data)
|
||||
{
|
||||
struct dive *dive = current_dive;
|
||||
cairo_t *cr;
|
||||
struct graphics_context gc;
|
||||
int w,h;
|
||||
|
||||
w = widget->allocation.width;
|
||||
h = widget->allocation.height;
|
||||
|
||||
cr = gdk_cairo_create(widget->window);
|
||||
cairo_set_source_rgb(cr, 0, 0, 0);
|
||||
cairo_paint(cr);
|
||||
gc.cr = gdk_cairo_create(widget->window);
|
||||
cairo_set_source_rgb(gc.cr, 0, 0, 0);
|
||||
cairo_paint(gc.cr);
|
||||
|
||||
if (dive)
|
||||
plot(cr, w, h, dive);
|
||||
plot(&gc, w, h, dive);
|
||||
|
||||
cairo_destroy(cr);
|
||||
cairo_destroy(gc.cr);
|
||||
|
||||
return FALSE;
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in a new issue