From 8e28a79e88c344023a036758bb9793549f29829f Mon Sep 17 00:00:00 2001
From: hippoz <10706925-hippoz@users.noreply.gitlab.com>
Date: Tue, 25 Apr 2023 17:50:05 +0300
Subject: [PATCH] greatly improve performance by caching text size

---
 src/text-node.c | 33 ++++++++++++++++++---------------
 src/text-node.h |  3 +++
 2 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/src/text-node.c b/src/text-node.c
index 1b7684a..aed844a 100644
--- a/src/text-node.c
+++ b/src/text-node.c
@@ -17,6 +17,9 @@ UITextNode *text_node_new(UINode *parent, PangoFontDescription *desc, UIRGBA col
     n->color = color;
     n->caret_index = -1;
     n->caret_node = NULL;
+    n->computed_dimensions_invalid = true;
+    n->computed_text_width = 0;
+    n->computed_text_height = 0;
     n->node.text = "text";
     n->node.handle_proto = text_node_handle;
     node_attach(parent, (UINode*)n);
@@ -47,6 +50,7 @@ int text_node_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
             n->layout = layout;
             n->pending_text = NULL;
         }
+        n->computed_dimensions_invalid = true;
     }
 
     switch (ev) {
@@ -59,23 +63,22 @@ int text_node_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
             cairo_fill(n->node.drw);
             break;
         }
-        case UI_EVENT_GET_WIDTH: {
-            if (!n->layout) {
-                break;
-            }
-            int w;
-            pango_layout_get_size(n->layout, &w, NULL);
-            *(double*)p = pango_units_to_double(w);
-            return 1;
-        }
+        case UI_EVENT_GET_WIDTH: /* through */
         case UI_EVENT_GET_HEIGHT: {
-            if (!n->layout) {
-                break;
+            if (n->computed_dimensions_invalid) {
+                int w, h = 0;
+                pango_layout_get_size(n->layout, &w, &h);
+                n->computed_text_width = pango_units_to_double(w);
+                n->computed_text_height = pango_units_to_double(h);
+                n->computed_dimensions_invalid = false;
             }
-            int h;
-            pango_layout_get_size(n->layout, NULL, &h);
-            *(double*)p = pango_units_to_double(h);
-            return 1;
+            if (ev == UI_EVENT_GET_WIDTH) {
+                *(double*)p = n->computed_text_width;
+            }
+            if (ev == UI_EVENT_GET_HEIGHT) {
+                *(double*)p = n->computed_text_height;
+            }
+            break;
         }
         case UI_EVENT_RELAYOUT: {
             if (!n->layout) {
diff --git a/src/text-node.h b/src/text-node.h
index dc5b9de..ffacd9d 100644
--- a/src/text-node.h
+++ b/src/text-node.h
@@ -15,6 +15,9 @@ typedef struct UITextNode {
     UIRGBA color;
     ssize_t caret_index;
     UINode *caret_node;
+    double computed_text_width;
+    double computed_text_height;
+    bool computed_dimensions_invalid;
 } UITextNode;
 
 int text_node_handle(UINode *node, enum UIEvent ev, size_t d, void *p);