From a4b60e7eef785184cb58c3cecf42dbc32baad3f1 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 31 Jul 2019 20:02:48 +0530
Subject: [PATCH] Disable the ``liga`` and ``dlig`` OpenType features so that
 kitty works with "so-called" monospace fonts such as Nimbus Mono that have
 non-programming ligatures.

---
 docs/changelog.rst |  4 ++++
 kitty/fonts.c      | 24 ++++++++++++------------
 2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 1988996cb..332902589 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -10,6 +10,10 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Dont fail to start if running the shell to read the EDITOR env var fails
   (:iss:`1869`)
 
+- Disable the ``liga`` and ``dlig`` OpenType features so that kitty works with
+  "so-called" monospace fonts such as Nimbus Mono that have non-programming
+  ligatures.
+
 
 0.14.3 [2019-07-29]
 ---------------------
diff --git a/kitty/fonts.c b/kitty/fonts.c
index f68754f92..18592b972 100644
--- a/kitty/fonts.c
+++ b/kitty/fonts.c
@@ -58,7 +58,7 @@ typedef struct {
 
 
 static hb_buffer_t *harfbuzz_buffer = NULL;
-static hb_feature_t no_calt_feature = {0};
+static hb_feature_t hb_features[3] = {{0}};
 static char_type shape_buffer[4096] = {0};
 static size_t max_texture_size = 1024, max_array_len = 1024;
 
@@ -739,11 +739,8 @@ shape(CPUCell *first_cpu_cell, GPUCell *first_gpu_cell, index_type num_cells, hb
     group_state.last_gpu_cell = first_gpu_cell + (num_cells ? num_cells - 1 : 0);
     load_hb_buffer(first_cpu_cell, first_gpu_cell, num_cells);
 
-    if (disable_ligature) {
-        hb_shape(font, harfbuzz_buffer, &no_calt_feature, 1);
-    } else {
-        hb_shape(font, harfbuzz_buffer, NULL, 0);
-    }
+    size_t num_features = arraysz(hb_features) - (disable_ligature ? 0 : 1);
+    hb_shape(font, harfbuzz_buffer, hb_features, num_features);
 
     unsigned int info_length, positions_length;
     group_state.info = hb_buffer_get_glyph_infos(harfbuzz_buffer, &info_length);
@@ -1414,12 +1411,15 @@ init_fonts(PyObject *module) {
     harfbuzz_buffer = hb_buffer_create();
     if (harfbuzz_buffer == NULL || !hb_buffer_allocation_successful(harfbuzz_buffer) || !hb_buffer_pre_allocate(harfbuzz_buffer, 2048)) { PyErr_NoMemory(); return false; }
     hb_buffer_set_cluster_level(harfbuzz_buffer, HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
-#define feature_str "-calt"
-    if (!hb_feature_from_string(feature_str, sizeof(feature_str) - 1, &no_calt_feature)) {
-        PyErr_SetString(PyExc_RuntimeError, "Failed to create -calt harfbuzz feature");
-        return false;
-    }
-#undef feature_str
+#define create_feature(feature, where) {\
+    if (!hb_feature_from_string(feature, sizeof(feature) - 1, &hb_features[where])) { \
+        PyErr_SetString(PyExc_RuntimeError, "Failed to create " feature " harfbuzz feature"); \
+        return false; \
+    }}
+    create_feature("-liga", 0);
+    create_feature("-dlig", 1);
+    create_feature("-calt", 2);
+#undef create_feature
     if (PyModule_AddFunctions(module, module_methods) != 0) return false;
     current_send_sprite_to_gpu = send_sprite_to_gpu;
     return true;