feat: text node support

meson.build

@@ -37,6 +37,9 @@ pcre2_dep = dependency('libpcre2-8')
 libscenefx_dep = dependency('scenefx-0.4',version: '>=0.4.1')
 pixman_dep = dependency('pixman-1')
 cjson_dep = dependency('libcjson')
+cairo_dep = dependency('cairo')
+pango_dep = dependency('pango')
+pangocairo_dep = dependency('pangocairo')
 
 # version info
 git = find_program('git', required : false)
@@ -94,6 +97,7 @@ endif
 executable('mango',
   'src/mango.c',
   'src/common/util.c',
+  'src/draw/text-node.c',
   'src/ext-protocol/wlr_ext_workspace_v1.c',
   wayland_sources,
   dependencies : [
@@ -109,6 +113,9 @@ executable('mango',
     pcre2_dep,
     pixman_dep,
     cjson_dep,
+    cairo_dep,
+    pango_dep,
+    pangocairo_dep,
   ],
   install : true,
   c_args : c_args,

src/draw/text-node.c

@@ -0,0 +1,140 @@
+#include "text-node.h"
+#include <stdlib.h>
+#include <cairo.h>
+#include <pango/pangocairo.h>
+#include <wlr/interfaces/wlr_buffer.h>
+#include <wayland-server-core.h>
+#include <drm_fourcc.h>
+
+// 自定义 wlr_buffer，用于将 Cairo Surface 包装并注入 wlr_scene
+struct mango_text_buffer {
+    struct wlr_buffer base;
+    cairo_surface_t *surface;
+};
+
+static void text_buffer_destroy(struct wlr_buffer *wlr_buffer) {
+    struct mango_text_buffer *buf = wl_container_of(wlr_buffer, buf, base);
+    cairo_surface_destroy(buf->surface);
+    free(buf);
+}
+
+static bool text_buffer_begin_data_ptr_access(struct wlr_buffer *wlr_buffer,
+                                              uint32_t flags,
+                                              void **data,
+                                              uint32_t *format,
+                                              size_t *stride) {
+    (void)flags; // 该参数当前无需使用
+    struct mango_text_buffer *buf = wl_container_of(wlr_buffer, buf, base);
+    *data = cairo_image_surface_get_data(buf->surface);
+    *format = DRM_FORMAT_ARGB8888;
+    *stride = cairo_image_surface_get_stride(buf->surface);
+    return true;
+}
+
+static void text_buffer_end_data_ptr_access(struct wlr_buffer *wlr_buffer) {
+    // Cairo 表面数据在 flush 后稳定，此处无需额外操作
+}
+
+static const struct wlr_buffer_impl text_buffer_impl = {
+    .destroy = text_buffer_destroy,
+    .begin_data_ptr_access = text_buffer_begin_data_ptr_access,
+    .end_data_ptr_access = text_buffer_end_data_ptr_access,
+};
+
+struct mango_text_node *mango_text_node_create(struct wlr_scene_tree *parent) {
+    struct mango_text_node *node = calloc(1, sizeof(*node));
+    if (!node) return NULL;
+
+    node->scene_buffer = wlr_scene_buffer_create(parent, NULL);
+    if (!node->scene_buffer) {
+        free(node);
+        return NULL;
+    }
+    return node;
+}
+
+void mango_text_node_update(struct mango_text_node *node, const char *text,
+                            const char *font_desc, float color[4], float scale) {
+    if (!node || !text || !font_desc) return;
+    if (scale <= 0.0f) scale = 1.0f;
+
+    // 测量文字像素尺寸
+    cairo_surface_t *dummy_surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1, 1);
+    cairo_t *dummy_cr = cairo_create(dummy_surface);
+    PangoContext *dummy_ctx = pango_cairo_create_context(dummy_cr);
+    pango_cairo_context_set_resolution(dummy_ctx, 96.0 * scale);
+    PangoLayout *dummy_layout = pango_layout_new(dummy_ctx);
+    PangoFontDescription *desc = pango_font_description_from_string(font_desc);
+    pango_layout_set_font_description(dummy_layout, desc);
+    pango_layout_set_text(dummy_layout, text, -1);
+
+    int pixel_width, pixel_height;
+    pango_layout_get_pixel_size(dummy_layout, &pixel_width, &pixel_height);
+
+    g_object_unref(dummy_layout);
+    pango_font_description_free(desc);
+    g_object_unref(dummy_ctx);
+    cairo_destroy(dummy_cr);
+    cairo_surface_destroy(dummy_surface);
+
+    if (pixel_width <= 0 || pixel_height <= 0) {
+        wlr_scene_buffer_set_buffer(node->scene_buffer, NULL);
+        node->logical_width = 0;
+        node->logical_height = 0;
+        return;
+    }
+
+    // 创建真实大小的 Surface 并绘制文字
+    cairo_surface_t *surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, pixel_width, pixel_height);
+    cairo_t *cr = cairo_create(surface);
+
+    cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 0.0);
+    cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
+    cairo_paint(cr);
+    cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
+
+    PangoContext *ctx = pango_cairo_create_context(cr);
+    pango_cairo_context_set_resolution(ctx, 96.0 * scale);
+    PangoLayout *layout = pango_layout_new(ctx);
+    desc = pango_font_description_from_string(font_desc);
+    pango_layout_set_font_description(layout, desc);
+    pango_layout_set_text(layout, text, -1);
+
+    cairo_set_source_rgba(cr, color[0], color[1], color[2], color[3]);
+    pango_cairo_show_layout(cr, layout);
+    cairo_surface_flush(surface);
+
+    // 包装成 wlr_buffer
+    struct mango_text_buffer *buf = calloc(1, sizeof(*buf));
+    if (!buf) {
+        cairo_surface_destroy(surface);
+        cairo_destroy(cr);
+        g_object_unref(layout);
+        pango_font_description_free(desc);
+        g_object_unref(ctx);
+        return;
+    }
+    wlr_buffer_init(&buf->base, &text_buffer_impl, pixel_width, pixel_height);
+    buf->surface = surface;
+
+    // 提交给场景图
+    wlr_scene_buffer_set_buffer(node->scene_buffer, &buf->base);
+    wlr_buffer_drop(&buf->base); // 函数内引用计数 -1，交给场景图管理
+
+    // 设置逻辑大小，实现 HiDPI 缩放
+    node->logical_width = (int)(pixel_width / scale);
+    node->logical_height = (int)(pixel_height / scale);
+    wlr_scene_buffer_set_dest_size(node->scene_buffer, node->logical_width, node->logical_height);
+
+    // 清理绘制资源
+    g_object_unref(layout);
+    pango_font_description_free(desc);
+    g_object_unref(ctx);
+    cairo_destroy(cr);
+}
+
+void mango_text_node_destroy(struct mango_text_node *node) {
+    if (!node) return;
+    wlr_scene_node_destroy(&node->scene_buffer->node);
+    free(node);
+}

src/draw/text-node.h

@@ -0,0 +1,34 @@
+#ifndef MANGO_TEXT_H
+#define MANGO_TEXT_H
+
+#include <wlr/types/wlr_scene.h>
+
+struct mango_text_node {
+    struct wlr_scene_buffer *scene_buffer;
+    int logical_width;
+    int logical_height;
+};
+
+/**
+ * 创建一个独立的文字场景节点
+ * @param parent 父级场景树节点（例如窗口装饰树、OSD层树或状态栏树）
+ */
+struct mango_text_node *mango_text_node_create(struct wlr_scene_tree *parent);
+
+/**
+ * 更新节点中的文字内容、字体、颜色和缩放
+ * @param node 文字节点指针
+ * @param text 要显示的文本内容
+ * @param font_desc Pango 字体描述字符串 (例如 "Sans 12" 或 "JetBrains Mono Bold 14")
+ * @param color RGBA 颜色数组，范围 0.0 ~ 1.0
+ * @param scale 当前输出设备的缩放比例 (HiDPI 支持)
+ */
+void mango_text_node_update(struct mango_text_node *node, const char *text,
+                            const char *font_desc, float color[4], float scale);
+
+/**
+ * 销毁文字节点并释放相关场景图资源
+ */
+void mango_text_node_destroy(struct mango_text_node *node);
+
+#endif /* MANGO_TEXT_H */

src/mango.c

@@ -96,6 +96,7 @@
 #include <xcb/xcb_icccm.h>
 #endif
 #include "common/util.h"
+#include "draw/text-node.h"
 
 /* macros */
 #define MAX(A, B) ((A) > (B) ? (A) : (B))
@@ -327,6 +328,7 @@ struct Client {
 	struct wlr_scene_shadow *shadow;
 	struct wlr_scene_tree *scene_surface;
 	struct wlr_scene_tree *overview_scene_surface;
+	struct mango_text_node *text_node;
 	struct wl_list link;
 	struct wl_list flink;
 	struct wl_list fadeout_link;
@@ -4513,6 +4515,11 @@ mapnotify(struct wl_listener *listener, void *data) {
 #endif
 	// extra node
 
+	c->text_node =  mango_text_node_create(c->scene);
+	mango_text_node_update(c->text_node, "hello world", "Sans 50", config.focuscolor, 1.0f);
+	wlr_scene_node_lower_to_bottom(&c->text_node->scene_buffer->node);
+	wlr_scene_node_set_enabled(&c->text_node->scene_buffer->node, false);
+
 	for (i = 0; i < 2; i++) {
 		c->splitindicator[i] = wlr_scene_rect_create(
 			c->scene, 0, 0,