use cairo groups instead of writing the double-buffering code myself

pretty much equivalent, but a lot simpler

4 files changed, 24 insertions, 59 deletions

diff --git a/src/display.c b/src/display.c
index c26c692..83ee9d9 100644
--- a/src/display.c
+++ b/src/display.c
@@ -22,30 +22,11 @@ void runes_display_init(RunesDisplay *display, char *font_name)
     runes_display_recalculate_font_metrics(display, font_name);
 }
 
-void runes_display_set_window_size(RunesTerm *t, int width, int height)
+void runes_display_set_context(RunesTerm *t, cairo_t *cr)
 {
     RunesDisplay *display = t->display;
-    cairo_t *old_cr = NULL;
-    cairo_surface_t *surface;
 
-    if (width == display->xpixel && height == display->ypixel) {
-        return;
-    }
-
-    display->xpixel = width;
-    display->ypixel = height;
-
-    old_cr = display->cr;
-
-    /* XXX this should really use cairo_surface_create_similar_image, but when
-     * i did that, drawing calls would occasionally block until an X event
-     * occurred for some reason. should look into this, because i think
-     * create_similar_image does things that are more efficient (using some
-     * xlib shm stuff) */
-    surface = cairo_image_surface_create(
-        CAIRO_FORMAT_RGB24, display->xpixel, display->ypixel);
-    display->cr = cairo_create(surface);
-    cairo_surface_destroy(surface);
+    display->cr = cr;
     if (display->layout) {
         pango_cairo_update_layout(display->cr, display->layout);
     }
@@ -63,24 +44,6 @@ void runes_display_set_window_size(RunesTerm *t, int width, int height)
         pango_attr_list_unref(attrs);
         pango_font_description_free(font_desc);
     }
-
-    cairo_save(display->cr);
-
-    if (old_cr) {
-        cairo_set_source_surface(
-            display->cr, cairo_get_target(old_cr), 0.0, 0.0);
-    }
-    else {
-        cairo_set_source(display->cr, t->config->bgdefault);
-    }
-
-    cairo_paint(display->cr);
-
-    cairo_restore(display->cr);
-
-    if (old_cr) {
-        cairo_destroy(old_cr);
-    }
 }
 
 void runes_display_draw_screen(RunesTerm *t)
@@ -96,6 +59,8 @@ void runes_display_draw_screen(RunesTerm *t)
         display->has_selection = 0;
     }
 
+    cairo_push_group(display->cr);
+
     /* XXX quite inefficient */
     rows = t->scr->grid->max.row;
     for (r = 0; r < rows; ++r) {
@@ -106,11 +71,14 @@ void runes_display_draw_screen(RunesTerm *t)
         }
     }
 
+    cairo_pop_group_to_source(display->cr);
+    cairo_paint(display->cr);
+
     t->scr->dirty = 0;
     display->dirty = 0;
 }
 
-void runes_display_draw_cursor(RunesTerm *t, cairo_t *cr)
+void runes_display_draw_cursor(RunesTerm *t)
 {
     RunesDisplay *display = t->display;
 
@@ -128,30 +96,31 @@ void runes_display_draw_cursor(RunesTerm *t, cairo_t *cr)
             width *= 2;
         }
 
-        cairo_save(cr);
-        cairo_set_source(cr, t->config->cursorcolor);
+        cairo_push_group(display->cr);
+        cairo_set_source(display->cr, t->config->cursorcolor);
         if (display->unfocused) {
-            cairo_set_line_width(cr, 1);
+            cairo_set_line_width(display->cr, 1);
             cairo_rectangle(
-                cr,
+                display->cr,
                 col * display->fontx + 0.5,
                 (row + display->row_visible_offset) * display->fonty + 0.5,
                 width - 1, display->fonty - 1);
-            cairo_stroke(cr);
+            cairo_stroke(display->cr);
         }
         else {
             cairo_rectangle(
-                cr,
+                display->cr,
                 col * display->fontx,
                 (row + display->row_visible_offset) * display->fonty,
                 width, display->fonty);
-            cairo_fill(cr);
+            cairo_fill(display->cr);
             runes_display_draw_glyph(
-                t, cr, t->config->bgdefault, cell->attrs,
+                t, display->cr, t->config->bgdefault, cell->attrs,
                 cell->contents, cell->len,
                 row + display->row_visible_offset, col);
         }
-        cairo_restore(cr);
+        cairo_pop_group_to_source(display->cr);
+        cairo_paint(display->cr);
     }
 }
 
@@ -218,7 +187,6 @@ int runes_display_loc_is_between(
 void runes_display_cleanup(RunesDisplay *display)
 {
     g_object_unref(display->layout);
-    cairo_destroy(display->cr);
 }
 
 static void runes_display_recalculate_font_metrics(
diff --git a/src/display.h b/src/display.h
index ba2bb13..4230fc4 100644
--- a/src/display.h
+++ b/src/display.h
@@ -25,9 +25,9 @@ struct runes_display {
 };
 
 void runes_display_init(RunesDisplay *display, char *font_name);
-void runes_display_set_window_size(RunesTerm *t, int width, int height);
+void runes_display_set_context(RunesTerm *t, cairo_t *cr);
 void runes_display_draw_screen(RunesTerm *t);
-void runes_display_draw_cursor(RunesTerm *t, cairo_t *cr);
+void runes_display_draw_cursor(RunesTerm *t);
 int runes_display_loc_is_selected(RunesTerm *t, struct vt100_loc loc);
 int runes_display_loc_is_between(
     RunesTerm *t, struct vt100_loc loc,
diff --git a/src/term.c b/src/term.c
index 84d7f4f..0584653 100644
--- a/src/term.c
+++ b/src/term.c
@@ -30,9 +30,10 @@ void runes_term_init(RunesTerm *t, RunesLoop *loop, int argc, char *argv[])
     t->scr = calloc(1, sizeof(VT100Screen));
     vt100_screen_init(t->scr);
 
+    vt100_screen_set_scrollback_length(t->scr, t->config->scrollback_length);
     runes_window_backend_create_window(t, argc, argv);
     runes_pty_backend_spawn_subprocess(t);
-    vt100_screen_set_scrollback_length(t->scr, t->config->scrollback_length);
+    runes_display_set_context(t, t->w->backend_cr);
 
     runes_window_backend_get_size(t, &width, &height);
     runes_term_set_window_size(t, width, height);
@@ -45,7 +46,6 @@ void runes_term_set_window_size(RunesTerm *t, int xpixel, int ypixel)
 {
     int row = ypixel / t->display->fonty, col = xpixel / t->display->fontx;
 
-    runes_display_set_window_size(t, xpixel, ypixel);
     runes_pty_backend_set_window_size(t, row, col, xpixel, ypixel);
     vt100_screen_set_window_size(t->scr, row, col);
 }
diff --git a/src/window-xlib.c b/src/window-xlib.c
index 68930d2..20f4eee 100644
--- a/src/window-xlib.c
+++ b/src/window-xlib.c
@@ -519,11 +519,7 @@ static void runes_window_backend_flush(RunesTerm *t)
     }
 
     runes_display_draw_screen(t);
-
-    cairo_set_source_surface(
-        w->backend_cr, cairo_get_target(t->display->cr), 0.0, 0.0);
-    cairo_paint(w->backend_cr);
-    runes_display_draw_cursor(t, w->backend_cr);
+    runes_display_draw_cursor(t);
     cairo_surface_flush(cairo_get_target(w->backend_cr));
 
     clock_gettime(CLOCK_REALTIME, &w->last_redraw);
@@ -879,6 +875,7 @@ static void runes_window_backend_handle_expose_event(
 {
     UNUSED(e);
 
+    t->display->dirty = 1;
     runes_window_backend_flush(t);
 }