Implement rendering of titles in CSD

glfw/glfw3.h

@@ -1683,7 +1683,7 @@ typedef void (* GLFWjoystickfun)(int,int);
 
 typedef void (* GLFWuserdatafun)(unsigned long long, void*);
 typedef void (* GLFWtickcallback)(void*);
-typedef void (* GLFWdrawtextfun)(const char *text, uint32_t fg, uint32_t bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset);
+typedef bool (* GLFWdrawtextfun)(GLFWwindow *window, const char *text, uint32_t fg, uint32_t bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset);
 
 /*! @brief Video mode type.
  *

glfw/wl_client_side_decorations.c

@@ -50,6 +50,9 @@ alloc_buffer_pair(_GLFWWaylandBufferPair *pair, struct wl_shm_pool *pool, uint8_
 static void
 render_title_bar(_GLFWwindow *window, bool to_front_buffer) {
     uint8_t *output = to_front_buffer ? decs.top.buffer.data.front : decs.top.buffer.data.back;
+    if (window->wl.title && window->wl.title[0] && _glfw.callbacks.draw_text) {
+        if (_glfw.callbacks.draw_text((GLFWwindow*)window, window->wl.title, 0, bg_color, output, decs.top.buffer.width, decs.top.buffer.height, 10, 0)) return;
+    }
     for (uint32_t *px = (uint32_t*)output, *end = (uint32_t*)(output + decs.top.buffer.size_in_bytes); px < end; px++) {
         *px = bg_color;
     }

glfw/wl_window.c

@@ -817,7 +817,10 @@ void _glfwPlatformDestroyWindow(_GLFWwindow* window)
 
 void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char* title)
 {
-    if (window->wl.title) free(window->wl.title);
+    if (window->wl.title) {
+        if (title && strcmp(title, window->wl.title) == 0) return;
+        free(window->wl.title);
+    } else if (!title) return;
     // Wayland cannot handle requests larger than ~8200 bytes. Sending
     // one causes an abort(). Since titles this large are meaningless anyway
     // ensure they do not happen.

kitty/freetype_render_ui_text.c

@@ -99,7 +99,7 @@ load_font(FontConfigFace *info, Face *ans) {
 
 static bool
 ensure_state(void) {
-    if (main_face.freetype && main_face.hb) return false;
+    if (main_face.freetype && main_face.hb) return true;
     if (!information_for_font_family(main_face_family.name, main_face_family.bold, main_face_family.italic, &main_face_information)) return false;
     if (!load_font(&main_face_information, &main_face)) return false;
     hb_buffer = hb_buffer_create();
@@ -147,6 +147,7 @@ typedef struct RenderState {
     Face *current_face;
     float x, y;
     Region src, dest;
+    unsigned sz_px;
 } RenderState;
 
 static void
@@ -227,7 +228,7 @@ render_run(RenderState *rs) {
     }
     FT_Face face = rs->current_face->freetype;
     bool has_color = FT_HAS_COLOR(face);
-    FT_UInt pixel_size = 3 * rs->output_height / 4;
+    FT_UInt pixel_size = rs->sz_px;
     set_pixel_size(rs->current_face, pixel_size, has_color);
     hb_shape(rs->current_face->hb, hb_buffer, NULL, 0);
     unsigned int len = hb_buffer_get_length(hb_buffer);
@@ -327,7 +328,7 @@ process_codepoint(RenderState *rs, char_type codep, char_type next_codep) {
 }
 
 bool
-render_single_line(const char *text, pixel fg, pixel bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset) {
+render_single_line(const char *text, unsigned sz_px, pixel fg, pixel bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset) {
     if (!ensure_state()) return false;
     bool has_text = text && text[0];
     pixel pbg = premult_pixel(bg, ((bg >> 24) & 0xff));
@@ -343,7 +344,7 @@ render_single_line(const char *text, pixel fg, pixel bg, uint8_t *output_buf, si
     text_len = decode_utf8_string(text, text_len, unicode);
     RenderState rs = {
         .current_face = &main_face, .fg = fg, .bg = bg, .output_width = width, .output_height = height,
-        .output = (pixel*)output_buf, .x = x_offset, .y = y_offset
+        .output = (pixel*)output_buf, .x = x_offset, .y = y_offset, .sz_px = sz_px
     };
 
     for (size_t i = 0; i < text_len && rs.x < rs.output_width; i++) {
@@ -376,7 +377,7 @@ render_line(PyObject *self UNUSED, PyObject *args, PyObject *kw) {
     PyObject *ans = PyBytes_FromStringAndSize(NULL, width * height * 4);
     if (!ans) return NULL;
     uint8_t *buffer = (u_int8_t*) PyBytes_AS_STRING(ans);
-    if (!render_single_line(text, 0, 0xffffffff, buffer, width, height, x_offset, y_offset)) {
+    if (!render_single_line(text, 3 * height / 4, 0, 0xffffffff, buffer, width, height, x_offset, y_offset)) {
         Py_CLEAR(ans);
         if (!PyErr_Occurred()) PyErr_SetString(PyExc_RuntimeError, "Unknown error while rendering text");
         ans = NULL;

kitty/freetype_render_ui_text.h

@@ -9,7 +9,7 @@
 #include "data-types.h"
 #include <hb-ft.h>
 
-bool render_single_line(const char *text, uint32_t fg, uint32_t bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset);
+bool render_single_line(const char *text, unsigned sz_px, uint32_t fg, uint32_t bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset);
 
 typedef struct FontConfigFace {
     char *path;

kitty/glfw-wrapper.h

@@ -1421,7 +1421,7 @@ typedef void (* GLFWjoystickfun)(int,int);
 
 typedef void (* GLFWuserdatafun)(unsigned long long, void*);
 typedef void (* GLFWtickcallback)(void*);
-typedef void (* GLFWdrawtextfun)(const char *text, uint32_t fg, uint32_t bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset);
+typedef bool (* GLFWdrawtextfun)(GLFWwindow *window, const char *text, uint32_t fg, uint32_t bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset);
 
 /*! @brief Video mode type.
  *

kitty/glfw.c

@@ -10,6 +10,9 @@
 #include "charsets.h"
 #include <structmember.h>
 #include "glfw-wrapper.h"
+#ifndef __APPLE__
+#include "freetype_render_ui_text.h"
+#endif
 extern bool cocoa_make_window_resizable(void *w, bool);
 extern void cocoa_focus_window(void *w);
 extern long cocoa_window_number(void *w);
@@ -381,12 +384,25 @@ application_close_requested_callback(int flags) {
     }
 }
 
+static inline void get_window_dpi(GLFWwindow *w, double *x, double *y);
+
 #ifdef __APPLE__
 static bool
 apple_file_open_callback(const char* filepath) {
     set_cocoa_pending_action(OPEN_FILE, filepath);
     return true;
 }
+#else
+
+static bool
+draw_text_callback(GLFWwindow *window, const char *text, uint32_t fg, uint32_t bg, uint8_t *output_buf, size_t width, size_t height, float x_offset, float y_offset) {
+    if (!set_callback_window(window)) return false;
+    double xdpi, ydpi;
+    get_window_dpi(window, &xdpi, &ydpi);
+    unsigned px_sz = (unsigned)(global_state.callback_os_window->font_sz_in_pts * ydpi / 72.);
+    px_sz = MIN(px_sz, 3 * height / 4);
+    return render_single_line(text, px_sz, fg, bg, output_buf, width, height, x_offset, y_offset);
+}
 #endif
 // }}}
 
@@ -855,6 +871,8 @@ glfw_init(PyObject UNUSED *self, PyObject *args) {
     if (ans == Py_True) {
 #ifdef __APPLE__
         glfwSetCocoaFileOpenCallback(apple_file_open_callback);
+#else
+        glfwSetDrawTextFunction(draw_text_callback);
 #endif
         OSWindow w = {0};
         set_os_window_dpi(&w);