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| Строка 1: |
Строка 1: |
| - | In this part of the Cairo graphics tutorial, we will create a custom GTK widget, where we will use the Cairo library.
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| - | == CPU widget ==
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| - |
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| - | In the next example we will create a CPU widget.
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| - |
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| - | <source lang="cpp">
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| - | /* cpu.h */
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| - |
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| - | #ifndef __CPU_H
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| - | #define __CPU_H
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| - |
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| - | #include <gtk/gtk.h>
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| - | #include <cairo.h>
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| - |
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| - | G_BEGIN_DECLS
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| - |
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| - |
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| - | #define GTK_CPU(obj) GTK_CHECK_CAST(obj, gtk_cpu_get_type (), GtkCpu)
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| - | #define GTK_CPU_CLASS(klass) GTK_CHECK_CLASS_CAST(klass, gtk_cpu_get_type(), GtkCpuClass)
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| - | #define GTK_IS_CPU(obj) GTK_CHECK_TYPE(obj, gtk_cpu_get_type())
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| - |
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| - |
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| - | typedef struct _GtkCpu GtkCpu;
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| - | typedef struct _GtkCpuClass GtkCpuClass;
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| - |
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| - |
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| - | struct _GtkCpu {
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| - | GtkWidget widget;
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| - |
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| - | gint sel;
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| - | };
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| - |
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| - | struct _GtkCpuClass {
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| - | GtkWidgetClass parent_class;
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| - | };
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| - |
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| - |
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| - | GtkType gtk_cpu_get_type(void);
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| - | void gtk_cpu_set_sel(GtkCpu *cpu, gint sel);
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| - | GtkWidget * gtk_cpu_new();
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| - |
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| - | G_END_DECLS
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| - |
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| - | #endif /* __CPU_H */
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| - | </source>
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| - |
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| - | <source lang="cpp">
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| - |
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| - | /* cpu.c */
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| - |
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| - | #include "cpu.h"
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| - |
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| - |
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| - | static void gtk_cpu_class_init(GtkCpuClass *klass);
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| - | static void gtk_cpu_init(GtkCpu *cpu);
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| - | static void gtk_cpu_size_request(GtkWidget *widget,
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| - | GtkRequisition *requisition);
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| - | static void gtk_cpu_size_allocate(GtkWidget *widget,
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| - | GtkAllocation *allocation);
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| - | static void gtk_cpu_realize(GtkWidget *widget);
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| - | static gboolean gtk_cpu_expose(GtkWidget *widget,
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| - | GdkEventExpose *event);
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| - | static void gtk_cpu_paint(GtkWidget *widget);
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| - | static void gtk_cpu_destroy(GtkObject *object);
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| - |
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| - |
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| - | GtkType
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| - | gtk_cpu_get_type(void)
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| - | {
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| - | static GtkType gtk_cpu_type = 0;
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| - |
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| - |
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| - | if (!gtk_cpu_type) {
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| - | static const GtkTypeInfo gtk_cpu_info = {
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| - | "GtkCpu",
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| - | sizeof(GtkCpu),
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| - | sizeof(GtkCpuClass),
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| - | (GtkClassInitFunc) gtk_cpu_class_init,
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| - | (GtkObjectInitFunc) gtk_cpu_init,
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| - | NULL,
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| - | NULL,
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| - | (GtkClassInitFunc) NULL
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| - | };
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| - | gtk_cpu_type = gtk_type_unique(GTK_TYPE_WIDGET, >k_cpu_info);
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| - | }
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| - |
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| - |
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| - | return gtk_cpu_type;
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| - | }
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| - |
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| - | void
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| - | gtk_cpu_set_state(GtkCpu *cpu, gint num)
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| - | {
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| - | cpu->sel = num;
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| - | gtk_cpu_paint(GTK_WIDGET(cpu));
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| - | }
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| - |
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| - |
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| - | GtkWidget * gtk_cpu_new()
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| - | {
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| - | return GTK_WIDGET(gtk_type_new(gtk_cpu_get_type()));
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| - | }
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| - |
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| - |
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| - | static void
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| - | gtk_cpu_class_init(GtkCpuClass *klass)
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| - | {
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| - | GtkWidgetClass *widget_class;
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| - | GtkObjectClass *object_class;
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| - |
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| - |
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| - | widget_class = (GtkWidgetClass *) klass;
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| - | object_class = (GtkObjectClass *) klass;
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| - |
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| - | widget_class->realize = gtk_cpu_realize;
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| - | widget_class->size_request = gtk_cpu_size_request;
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| - | widget_class->size_allocate = gtk_cpu_size_allocate;
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| - | widget_class->expose_event = gtk_cpu_expose;
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| - |
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| - | object_class->destroy = gtk_cpu_destroy;
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| - | }
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| - |
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| - |
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| - | static void
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| - | gtk_cpu_init(GtkCpu *cpu)
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| - | {
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| - | cpu->sel = 0;
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| - | }
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| - |
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| - |
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| - | static void
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| - | gtk_cpu_size_request(GtkWidget *widget,
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| - | GtkRequisition *requisition)
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| - | {
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| - | g_return_if_fail(widget != NULL);
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| - | g_return_if_fail(GTK_IS_CPU(widget));
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| - | g_return_if_fail(requisition != NULL);
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| - |
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| - | requisition->width = 80;
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| - | requisition->height = 100;
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| - | }
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| - |
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| - |
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| - | static void
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| - | gtk_cpu_size_allocate(GtkWidget *widget,
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| - | GtkAllocation *allocation)
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| - | {
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| - | g_return_if_fail(widget != NULL);
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| - | g_return_if_fail(GTK_IS_CPU(widget));
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| - | g_return_if_fail(allocation != NULL);
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| - |
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| - | widget->allocation = *allocation;
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| - |
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| - | if (GTK_WIDGET_REALIZED(widget)) {
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| - | gdk_window_move_resize(
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| - | widget->window,
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| - | allocation->x, allocation->y,
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| - | allocation->width, allocation->height
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| - | );
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| - | }
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| - | }
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| - |
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| - | static void
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| - | gtk_cpu_realize(GtkWidget *widget)
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| - | {
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| - | GdkWindowAttr attributes;
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| - | guint attributes_mask;
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| - |
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| - | g_return_if_fail(widget != NULL);
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| - | g_return_if_fail(GTK_IS_CPU(widget));
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| - |
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| - | GTK_WIDGET_SET_FLAGS(widget, GTK_REALIZED);
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| - |
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| - | attributes.window_type = GDK_WINDOW_CHILD;
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| - | attributes.x = widget->allocation.x;
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| - | attributes.y = widget->allocation.y;
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| - | attributes.width = 80;
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| - | attributes.height = 100;
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| - |
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| - | attributes.wclass = GDK_INPUT_OUTPUT;
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| - | attributes.event_mask = gtk_widget_get_events(widget) | GDK_EXPOSURE_MASK;
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| - |
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| - | attributes_mask = GDK_WA_X | GDK_WA_Y;
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| - |
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| - | widget->window = gdk_window_new(
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| - | gtk_widget_get_parent_window (widget),
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| - | & attributes, attributes_mask
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| - | );
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| - |
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| - | gdk_window_set_user_data(widget->window, widget);
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| - |
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| - | widget->style = gtk_style_attach(widget->style, widget->window);
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| - | gtk_style_set_background(widget->style, widget->window, GTK_STATE_NORMAL);
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| - | }
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| - | static gboolean
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| - | gtk_cpu_expose(GtkWidget *widget,
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| - | GdkEventExpose *event)
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| - | {
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| - | g_return_val_if_fail(widget != NULL, FALSE);
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| - | g_return_val_if_fail(GTK_IS_CPU(widget), FALSE);
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| - | g_return_val_if_fail(event != NULL, FALSE);
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| - |
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| - | gtk_cpu_paint(widget);
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| - |
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| - | return FALSE;
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| - | }
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| - |
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| - | static void
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| - | gtk_cpu_paint(GtkWidget *widget)
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| - | {
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| - | cairo_t *cr;
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| - |
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| - | cr = gdk_cairo_create(widget->window);
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| - |
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| - | cairo_translate(cr, 0, 7);
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| - |
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| - | cairo_set_source_rgb(cr, 0, 0, 0);
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| - | cairo_paint(cr);
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| - |
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| - | gint pos = GTK_CPU(widget)->sel;
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| - | gint rect = pos / 5;
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| - |
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| - | cairo_set_source_rgb(cr, 0.2, 0.4, 0);
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| - |
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| - | gint i;
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| - | for ( i = 1; i <= 20; i++) {
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| - | if (i > 20 - rect) {
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| - | cairo_set_source_rgb(cr, 0.6, 1.0, 0);
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| - | } else {
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| - | cairo_set_source_rgb(cr, 0.2, 0.4, 0);
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| - | }
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| - | cairo_rectangle(cr, 8, i*4, 30, 3);
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| - | cairo_rectangle(cr, 42, i*4, 30, 3);
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| - | cairo_fill(cr);
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| - | }
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| - |
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| - | cairo_destroy(cr);
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| - | }
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| - |
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| - |
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| - | static void
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| - | gtk_cpu_destroy(GtkObject *object)
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| - | {
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| - | GtkCpu *cpu;
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| - | GtkCpuClass *klass;
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| - |
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| - | g_return_if_fail(object != NULL);
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| - | g_return_if_fail(GTK_IS_CPU(object));
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| - |
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| - | cpu = GTK_CPU(object);
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| - |
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| - | klass = gtk_type_class(gtk_widget_get_type());
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| - |
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| - | if (GTK_OBJECT_CLASS(klass)->destroy) {
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| - | (* GTK_OBJECT_CLASS(klass)->destroy) (object);
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| - | }
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| - | }
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| - | </source>
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| - |
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| - | <source lang="cpp">
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| - | /* main.c */
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| - |
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| - | #include "cpu.h"
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| - |
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| - | static void set_value(GtkWidget * widget, gpointer data)
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| - | {
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| - | GdkRegion *region;
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| - |
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| - | GtkRange *range = (GtkRange *) widget;
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| - | GtkWidget *cpu = (GtkWidget *) data;
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| - | GTK_CPU(cpu)->sel = gtk_range_get_value(range);
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| - |
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| - | region = gdk_drawable_get_clip_region(cpu->window);
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| - | gdk_window_invalidate_region(cpu->window, region, TRUE);
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| - | gdk_window_process_updates(cpu->window, TRUE);
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| - | }
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| - | int main (int argc, char ** argv)
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| - | {
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| - | GtkWidget *window;
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| - | GtkWidget *cpu;
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| - | GtkWidget *fixed;
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| - | GtkWidget *scale;
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| - |
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| - | gtk_init(&argc, &argv);
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| - |
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| - |
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| - | window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
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| - | gtk_window_set_title(GTK_WINDOW(window), "CPU widget");
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| - | gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
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| - | gtk_window_set_default_size(GTK_WINDOW(window), 200, 180);
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| - |
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| - |
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| - | g_signal_connect(G_OBJECT(window), "destroy",
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| - | G_CALLBACK(gtk_main_quit), NULL);
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| - |
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| - | fixed = gtk_fixed_new();
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| - | gtk_container_add(GTK_CONTAINER(window), fixed);
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| - |
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| - | cpu = gtk_cpu_new();
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| - | gtk_fixed_put(GTK_FIXED(fixed), cpu, 30, 40);
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| - | scale = gtk_vscale_new_with_range(0.0, 100.0, 1.0);
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| - | gtk_range_set_inverted(GTK_RANGE(scale), TRUE);
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| - | gtk_scale_set_value_pos(GTK_SCALE(scale), GTK_POS_TOP);
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| - | gtk_widget_set_size_request(scale, 50, 120);
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| - | gtk_fixed_put(GTK_FIXED(fixed), scale, 130, 20);
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| - |
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| - | g_signal_connect(G_OBJECT(scale), "value_changed", G_CALLBACK(set_value), (gpointer) cpu);
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| - |
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| - | gtk_widget_show(cpu);
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| - | gtk_widget_show(fixed);
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| - | gtk_widget_show_all(window);
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| - | gtk_main();
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| - |
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| - | return 0;
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| - | }
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| - | </source>
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| - |
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| - | The CPU widget is a <b>GtkWidget</b>, on which we draw with Cairo API.
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| - | We draw a black background and 40 small rectangles. The rectangles are drawn in two colors.
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| - | Dark green and bright green color. The <b>GtkVScale</b> widget controls the number of the bright green rectangles drawn on the widget.
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| - | The example might look difficult at the first sight. But it is not that difficult after all. Most of the code is boilerplate, it always repeats, when we create a new widget.
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| - |
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| - | The drawing is done within the <b>gtk_cpu_paint()</b> function.
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| - |
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| - | <source lang="cpp">
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| - | cairo_t *cr;
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| - |
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| - | cr = gdk_cairo_create(widget->window);
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| - |
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| - | cairo_translate(cr, 0, 7);
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| - |
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| - | cairo_set_source_rgb(cr, 0, 0, 0);
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| - | cairo_paint(cr);
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| - | </source>
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| - |
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| - | As usual, we create a cairo context. We shift the origin 7 unit down. Next we paint the background of the widget to black color.
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| - |
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| - | <source lang="cpp">
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| - | gint pos = GTK_CPU(widget)->sel;
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| - | gint rect = pos / 5;
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| - | </source>
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| - |
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| - | Here we retrieve the sel number. It is the number that we got from the scale widget.
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| - | The slider has 100 numbers. The rect parameter makes a convertion from slider values into rectangles, that will be drawn in bright green color.
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| - |
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| - | <source lang="cpp">
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| - | gint i;
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| - | for ( i = 1; i <= 20; i++) {
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| - | if (i > 20 - rect) {
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| - | cairo_set_source_rgb(cr, 0.6, 1.0, 0);
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| - | } else {
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| - | cairo_set_source_rgb(cr, 0.2, 0.4, 0);
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| - | }
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| - | cairo_rectangle(cr, 8, i*4, 30, 3);
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| - | cairo_rectangle(cr, 42, i*4, 30, 3);
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| - | cairo_fill(cr);
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| - | }
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| - |
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| - | </source>
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| - |
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| - | Depending on the rect number, we draw 40 rectangles in two dark green color or in bright green color. Remember, that we are drawing these rectangles from top to bottom.
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| - |
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| - | <source lang="cpp">
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| - | GtkRange *range = (GtkRange *) widget;
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| - | GtkWidget *cpu = (GtkWidget *) data;
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| - | GTK_CPU(cpu)->sel = gtk_range_get_value(range);
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| - | </source>
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| - |
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| - | In the <b>set_value()</b> call, we get the reference to the CPU widget and set the sel value to current value, selected on the scale widget.
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| - |
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| - | <source lang="cpp">
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| - | GdkRegion *region;
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| - | ...
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| - | region = gdk_drawable_get_clip_region(cpu->window);
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| - | gdk_window_invalidate_region(cpu->window, region, TRUE);
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| - | gdk_window_process_updates(cpu->window, TRUE);
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| - | </source>
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| - |
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| - | This code invalides the complete window of the CPU widget and thus makes it redraw itself.
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| - |
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| - | [[image: gtk_faq_cpuwidget.png | center]]
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| - |
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| - | [[Категория:GTK+]]
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| - | [[Категория:Cairo]]
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