From dddff91fad0bbe5a438185f8a908da192c274aba Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sun, 6 Feb 2022 13:20:55 +0530
Subject: [PATCH] Linux: Fix rendering of emoji when using scalable fonts such
 as Segoe UI Emoji

---
 docs/changelog.rst              |  2 ++
 kitty/freetype.c                | 25 +++++++++++++------------
 kitty/freetype_render_ui_text.c |  4 ++--
 3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 8dffc93ea..083de6361 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -103,6 +103,8 @@ Detailed list of changes
   for the :doc:`launch <launch>` command to be used for pager positioning.
   (:iss:`4462`)
 
+- Linux: Fix rendering of emoji when using scalable fonts such as Segoe UI Emoji
+
 0.24.2 [2022-02-03]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/kitty/freetype.c b/kitty/freetype.c
index 0f4d12a86..5e187c06f 100644
--- a/kitty/freetype.c
+++ b/kitty/freetype.c
@@ -522,19 +522,20 @@ detect_right_edge(ProcessedBitmap *ans) {
 static bool
 render_color_bitmap(Face *self, int glyph_id, ProcessedBitmap *ans, unsigned int cell_width, unsigned int cell_height, unsigned int num_cells, unsigned int baseline UNUSED) {
     unsigned short best = 0, diff = USHRT_MAX;
-    const short limit = self->face->num_fixed_sizes;
-    for (short i = 0; i < limit; i++) {
-        unsigned short w = self->face->available_sizes[i].width;
-        unsigned short d = w > (unsigned short)cell_width ? w - (unsigned short)cell_width : (unsigned short)cell_width - w;
-        if (d < diff) {
-            diff = d;
-            best = i;
+    if (self->face->num_fixed_sizes > 0) {
+        const short limit = self->face->num_fixed_sizes;
+        for (short i = 0; i < limit; i++) {
+            unsigned short w = self->face->available_sizes[i].width;
+            unsigned short d = w > (unsigned short)cell_width ? w - (unsigned short)cell_width : (unsigned short)cell_width - w;
+            if (d < diff) {
+                diff = d;
+                best = i;
+            }
         }
-    }
-    FT_Error error = FT_Select_Size(self->face, best);
-    if (error) { set_freetype_error("Failed to set char size for non-scalable font, with error:", error); return false; }
-    if (!load_glyph(self, glyph_id, FT_LOAD_COLOR)) return false;
-    FT_Set_Char_Size(self->face, 0, self->char_height, self->xdpi, self->ydpi);
+        FT_Error error = FT_Select_Size(self->face, best);
+        if (error) { set_freetype_error("Failed to set char size for non-scalable font, with error:", error); return false; }
+    } else FT_Set_Char_Size(self->face, 0, self->char_height, self->xdpi, self->ydpi);
+    if (!load_glyph(self, glyph_id, FT_LOAD_COLOR | FT_LOAD_RENDER)) return false;
     FT_Bitmap *bitmap = &self->face->glyph->bitmap;
     if (bitmap->pixel_mode != FT_PIXEL_MODE_BGRA) return false;
     ans->buf = bitmap->buffer;
diff --git a/kitty/freetype_render_ui_text.c b/kitty/freetype_render_ui_text.c
index c5e3abfa2..7e514b9dc 100644
--- a/kitty/freetype_render_ui_text.c
+++ b/kitty/freetype_render_ui_text.c
@@ -134,7 +134,7 @@ choose_bitmap_size(FT_Face face, FT_UInt desired_height) {
 static void
 set_pixel_size(RenderCtx *ctx, Face *face, FT_UInt sz, bool get_metrics UNUSED) {
     if (sz != face->pixel_size) {
-        if (FT_HAS_COLOR(face->freetype)) sz = choose_bitmap_size(face->freetype, font_units_to_pixels_y(main_face.freetype, main_face.freetype->height));
+        if (face->freetype->num_fixed_sizes > 0 && FT_HAS_COLOR(face->freetype)) choose_bitmap_size(face->freetype, font_units_to_pixels_y(main_face.freetype, main_face.freetype->height));
         else FT_Set_Pixel_Sizes(face->freetype, sz, sz);
         hb_ft_font_changed(face->hb);
         hb_ft_font_set_load_flags(face->hb, get_load_flags(face->hinting, face->hintstyle, FT_LOAD_DEFAULT));
@@ -304,7 +304,7 @@ render_run(RenderCtx *ctx, RenderState *rs) {
     hb_glyph_info_t *info = hb_buffer_get_glyph_infos(hb_buffer, NULL);
     hb_glyph_position_t *positions = hb_buffer_get_glyph_positions(hb_buffer, NULL);
     int baseline = font_units_to_pixels_y(face, face->ascender);
-    int load_flags = get_load_flags(rs->current_face->hinting, rs->current_face->hintstyle, has_color ? FT_LOAD_COLOR : FT_LOAD_RENDER);
+    int load_flags = get_load_flags(rs->current_face->hinting, rs->current_face->hintstyle, FT_LOAD_RENDER | (has_color ? FT_LOAD_COLOR : 0));
     float pos = rs->x;
     unsigned int limit = len;
     for (unsigned int i = 0; i < len; i++) {