计算 bar 高度

src/CMakeLists.txt

@@ -19,7 +19,15 @@ project(${APP_NAME}
     LANGUAGES C
 )
 
-add_executable(${APP_NAME} wm.c utils.c buffer.c backtrace.c monitor.c client.c)
+add_executable(${APP_NAME}
+    wm.c
+    utils.c
+    buffer.c
+    backtrace.c
+    monitor.c
+    client.c
+    text.c
+)
 
 # use C23
 set_property(TARGET ${APP_NAME} PROPERTY C_STANDARD 23)
@@ -34,6 +42,9 @@ pkg_check_modules(deps REQUIRED
     xcb-randr
     xcb-xfixes
     xcb-xinerama
+
+    pango
+    pangocairo
 )
 
 target_include_directories(${APP_NAME} SYSTEM

src/default_config.h

@@ -1,3 +1,6 @@
+#include <stdint.h>
+
 static const char *const tags[] = {
   "1", "2", "3", "4", "5", "6", "7", "8", "9", nullptr,
 };
+static const uint32_t bar_y_padding = 1;

src/draw.h

@@ -1,3 +0,0 @@
-#pragma once
-
-

src/text.c

@@ -0,0 +1,92 @@
+#include "text.h"
+
+#include <glib-object.h>
+#include <glibconfig.h>
+#include <pango/pango-attributes.h>
+#include <pango/pango-context.h>
+#include <pango/pango-font.h>
+#include <pango/pango-fontmap.h>
+#include <pango/pango-layout.h>
+#include <pango/pango-types.h>
+#include <pango/pangocairo.h>
+#include <stdint.h>
+#include <stdio.h>
+
+static PangoContext *context = nullptr;
+static PangoLayout *layout = nullptr;
+static PangoAttrList *attr_list = nullptr;
+
+/**
+ * 初始化绘制文字的 pango 环境
+ * @param family 多个字体用逗号分割
+ * @param size 字体大小
+ * @param dpi
+ * @return layout 高度，可用于确定 bar 高度
+ */
+int text_init_pango_layout(const char *family, uint32_t size, uint32_t dpi) {
+  static const char *layout_family = nullptr;
+  static uint32_t layout_size = 0;
+  static uint32_t layout_dpi = 0;
+  static int text_height = 0;
+
+  if (layout_family != nullptr && strcmp(layout_family, family) == 0 &&
+      layout_size == size && layout_dpi == dpi) {
+    printf("text pango layout config cached\n");
+    return text_height;
+  }
+
+  text_clean_pango_layout();
+
+  layout_family = family;
+  layout_size = size;
+  layout_dpi = dpi;
+
+  PangoFontMap *fontmap = pango_cairo_font_map_new();
+  context = pango_font_map_create_context(fontmap);
+  pango_cairo_context_set_resolution(context, (double)dpi);
+
+  layout = pango_layout_new(context);
+
+  PangoFontDescription *desc = pango_font_description_from_string(family);
+  pango_font_description_set_size(desc, size * PANGO_SCALE);
+  PangoLanguage *lang = pango_context_get_language(context);
+  PangoFontMetrics *metrics = pango_context_get_metrics(context, desc, lang);
+
+  PangoAttribute *attr = pango_attr_font_desc_new(desc);
+  attr_list = pango_attr_list_new();
+  pango_attr_list_insert(attr_list, attr);
+
+  int height = pango_font_metrics_get_height(metrics);
+  int ascent = pango_font_metrics_get_ascent(metrics);
+  int descent = pango_font_metrics_get_descent(metrics);
+  text_height =
+    MAX(PANGO_PIXELS_CEIL(height), PANGO_PIXELS_CEIL(ascent + descent));
+
+  pango_font_metrics_unref(metrics);
+  pango_font_description_free(desc);
+  g_object_unref(fontmap);
+
+  PangoRectangle ink_rect, logical_rect;
+  pango_layout_get_pixel_extents(layout, &ink_rect, &logical_rect);
+
+  text_height = MAX(text_height, MAX(ink_rect.height, logical_rect.height));
+
+  return text_height;
+}
+
+void text_clean_pango_layout(void) {
+  if (attr_list) {
+    pango_attr_list_unref(attr_list);
+    attr_list = nullptr;
+  }
+
+  if (layout) {
+    g_object_unref(layout);
+    layout = nullptr;
+  }
+
+  if (context) {
+    g_object_unref(context);
+    context = nullptr;
+  }
+}

src/text.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include <stdint.h>
+
+int text_init_pango_layout(const char *family, uint32_t size, uint32_t dpi);
+void text_clean_pango_layout(void);

src/wm.c

@@ -20,6 +20,7 @@
 #include "buffer.h"
 #include "default_config.h"
 #include "monitor.h"
+#include "text.h"
 #include "types.h"
 #include "utils.h"
 
@@ -257,6 +258,11 @@ void wm_clean(void) {
 }
 
 static void wm_setup(void) {
+  int font_height = text_init_pango_layout("Terminus, Emacs Simsun", 10, 144);
+  wm.bar_height = (uint32_t)font_height + 2 * bar_y_padding;
+
+  printf("font height: %d, bar height: %u\n", font_height, wm.bar_height);
+
   for (monitor_t *m = wm.monitor_list; m; m = m->next) {
     monitor_initialize_tag(m, (const char **)tags);
   }

src/wm.h

@@ -1,8 +1,12 @@
 #pragma once
 
+#include <stdint.h>
+
 #include "types.h"
 
 typedef struct wm_t {
+  uint32_t bar_height;
+
   bool need_restart;
   GMainLoop *loop;