From 99ec8a898b7571c07fb322e2365b186df1681687 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Sun, 12 Feb 2017 16:36:12 -0500
Subject: avoid an allocation on every glyph string draw

probably not super meaningful compared to the cost of the cairo
operations, but may as well
---
 src/display.c | 27 +++++++++++++++++----------
 src/display.h |  2 ++
 src/term.c    |  1 +
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/display.c b/src/display.c
index 9c7ce87..59b7b14 100644
--- a/src/display.c
+++ b/src/display.c
@@ -44,6 +44,16 @@ RunesDisplay *runes_display_new(char *font_name)
     return display;
 }
 
+void runes_display_set_window_size(RunesTerm *t, int row, int col)
+{
+    RunesDisplay *display = t->display;
+
+    UNUSED(row);
+
+    free(display->glyph_buf);
+    display->glyph_buf = malloc(col * sizeof(cairo_glyph_t));
+}
+
 void runes_display_set_context(RunesTerm *t, cairo_t *cr)
 {
     RunesDisplay *display = t->display;
@@ -244,6 +254,7 @@ void runes_display_maybe_clear_selection(RunesTerm *t)
 void runes_display_delete(RunesDisplay *display)
 {
     free(display->ascii_glyph_index_cache);
+    free(display->glyph_buf);
     cairo_scaled_font_destroy(display->scaled_font);
     cairo_pattern_destroy(display->buffer);
     g_object_unref(display->layout);
@@ -492,37 +503,33 @@ static void runes_display_draw_glyphs_fast(
     size_t len, int row, int col)
 {
     RunesDisplay *display = t->display;
-    cairo_glyph_t *glyphs;
     size_t i;
 
-    glyphs = malloc(len * sizeof(cairo_glyph_t));
-
     for (i = 0; i < len; ++i) {
+        cairo_glyph_t *glyph = &display->glyph_buf[i];
         switch (cells[i]->len) {
         case 0:
-            glyphs[i].index = display->ascii_glyph_index_cache[' '];
+            glyph->index = display->ascii_glyph_index_cache[' '];
             break;
         case 1: {
             char c = cells[i]->contents[0];
-            glyphs[i].index = display->ascii_glyph_index_cache[(int)c];
+            glyph->index = display->ascii_glyph_index_cache[(int)c];
             break;
         }
         default:
             fprintf(stderr, "runes_display_draw_glyphs_fast requires ascii\n");
             return;
         }
-        glyphs[i].x = (col + i) * display->fontx;
-        glyphs[i].y = (row + 1) * display->fonty - display->font_descent;
+        glyph->x = (col + i) * display->fontx;
+        glyph->y = (row + 1) * display->fonty - display->font_descent;
     }
 
     cairo_save(display->cr);
     cairo_move_to(display->cr, col * display->fontx, row * display->fonty);
     cairo_set_source(display->cr, pattern);
     cairo_set_scaled_font(display->cr, display->scaled_font);
-    cairo_show_glyphs(display->cr, glyphs, len);
+    cairo_show_glyphs(display->cr, display->glyph_buf, len);
     cairo_restore(display->cr);
-
-    free(glyphs);
 }
 
 static void runes_display_draw_glyphs_slow(
diff --git a/src/display.h b/src/display.h
index e4ddc28..79ab068 100644
--- a/src/display.h
+++ b/src/display.h
@@ -11,6 +11,7 @@ struct runes_display {
     PangoLayout *layout;
     cairo_scaled_font_t *scaled_font;
     PangoGlyph *ascii_glyph_index_cache;
+    cairo_glyph_t *glyph_buf;
 
     int row_visible_offset;
 
@@ -31,6 +32,7 @@ struct runes_display {
 };
 
 RunesDisplay *runes_display_new(char *font_name);
+void runes_display_set_window_size(RunesTerm *t, int row, int col);
 void runes_display_set_context(RunesTerm *t, cairo_t *cr);
 void runes_display_draw_screen(RunesTerm *t);
 void runes_display_draw_cursor(RunesTerm *t);
diff --git a/src/term.c b/src/term.c
index 3477dab..bee110b 100644
--- a/src/term.c
+++ b/src/term.c
@@ -47,6 +47,7 @@ void runes_term_set_window_size(RunesTerm *t, int xpixel, int ypixel)
     int row = ypixel / t->display->fonty, col = xpixel / t->display->fontx;
 
     runes_pty_set_window_size(t, row, col, xpixel, ypixel);
+    runes_display_set_window_size(t, row, col);
     vt100_screen_set_window_size(t->scr, row, col);
 }
 
-- 
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