GTK 背景透明button (GtkImage + EventBox)

最新推荐文章于 2021-06-03 18:28:45 发布

liumf2005

最新推荐文章于 2021-06-03 18:28:45 发布

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分类专栏： gtk 文章标签： gtk button image object callback signal

本文链接：https://blog.youkuaiyun.com/liumf2005/article/details/7279885

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本文详细介绍了如何在GTK中利用GtkImage和EventBox组件创建具有透明背景的按钮。通过设置对象属性和响应信号回调，实现自定义的透明效果。

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#include <cairo.h>
#include <gtk/gtk.h>
#include <math.h>

static void
draw_round_rectangle (cairo_t * cr,
		      double x, double y,
		      double width, double height, double r)
{
  cairo_move_to (cr, x + r, y);
  cairo_line_to (cr, x + width - r, y);
  cairo_move_to (cr, x + width, y + r);
  cairo_line_to (cr, x + width, y + height - r);
  cairo_move_to (cr, x + width - r, y + height);
  cairo_line_to (cr, x + r, y + height);
  cairo_move_to (cr, x, y + height - r);
  cairo_line_to (cr, x, y + r);
  cairo_arc (cr, x + r, y + r, r, M_PI, 3 * M_PI / 2.0);
  cairo_arc (cr, x + width - r, y + r, r, 3 * M_PI / 2, 2 * M_PI);
  cairo_arc (cr, x + width - r, y + height - r, r, 0, M_PI / 2);
  cairo_arc (cr, x + r, y + height - r, r, M_PI / 2, M_PI);
}

gboolean on_expose_event (GtkWidget *widget, GdkEventExpose *event, cairo_surface_t *bg)
{
  cairo_t *cr;
  cairo_pattern_t *pattern;
  
  pattern = cairo_pattern_create_for_surface (bg);
  cairo_pattern_set_extend (pattern, CAIRO_EXTEND_REPEAT);
  
  cr = gdk_cairo_create (widget->window);
  
  cairo_set_source (cr, pattern);
  
  cairo_paint (cr);
  
  cairo_pattern_destroy (pattern);
  
  cairo_destroy (cr);
  
  return FALSE;
}

typedef struct _ImageButtonPrivate ImageButtonPrivate;
typedef struct _GroupWidget GroupWidget;

struct _ImageButtonPrivate
{
  gboolean         hovered;
  gboolean         activated;
  int              id;
  GroupWidget      *group;
};

struct _Group

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