1// ImGui GLFW binding with OpenGL3 + shaders
2// In this binding, ImTextureID is used to store an OpenGL 'GLuint' texture identifier. Read the FAQ about ImTextureID in imgui.cpp.
3
4// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
5// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
6// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
7// https://github.com/ocornut/imgui
8
9#include <stdio.h>
10
11#include "imgui/imgui.h"
12#include "imgui_impl_gtk3.h"
13
14#include <gtk/gtk.h>
15
16#define ARRAY_SIZE(arg) (sizeof(arg) / sizeof((arg)[0]))
17
18#define EVENT_MASK \
19    ((GdkEventMask)                  \
20    (GDK_STRUCTURE_MASK |            \
21     GDK_FOCUS_CHANGE_MASK |	     \
22     GDK_EXPOSURE_MASK |             \
23     GDK_PROPERTY_CHANGE_MASK |	     \
24     GDK_ENTER_NOTIFY_MASK |	     \
25     GDK_LEAVE_NOTIFY_MASK |	     \
26     GDK_KEY_PRESS_MASK |            \
27     GDK_KEY_RELEASE_MASK |	     \
28     GDK_BUTTON_PRESS_MASK |	     \
29     GDK_BUTTON_RELEASE_MASK |	     \
30     GDK_POINTER_MOTION_MASK |       \
31     GDK_SMOOTH_SCROLL_MASK |        \
32     GDK_SCROLL_MASK))
33
34// Data
35static GtkWidget*                      g_GtkGlArea = NULL;
36static guint64                         g_Time = 0;
37static bool                            g_MousePressed[5] = { false, false, false, false, false };
38static ImVec2                          g_MousePosition = ImVec2(-1, -1);
39static float                           g_MouseWheel = 0.0f;
40static int                             g_NumRedraws = 0;
41static guint                           g_RedrawTimeout = 0;
42
43static const char* ImGui_ImplGtk3_GetClipboardText(void* user_data)
44{
45    static char *last_clipboard = NULL;
46
47    g_clear_pointer(&last_clipboard, g_free);
48    last_clipboard = gtk_clipboard_wait_for_text(GTK_CLIPBOARD(user_data));
49    return last_clipboard;
50}
51
52static void ImGui_ImplGtk3_SetClipboardText(void* user_data, const char* text)
53{
54    gtk_clipboard_set_text(GTK_CLIPBOARD(user_data), text, -1);
55}
56
57void   ImGui_ImplGtk3_HandleEvent(GdkEvent *event)
58{
59    ImGuiIO& io = ImGui::GetIO();
60
61    GdkEventType type = gdk_event_get_event_type(event);
62    switch (type)
63    {
64    case GDK_MOTION_NOTIFY:
65    {
66        gdouble x = 0.0f, y = 0.0f;
67        if (gdk_event_get_coords(event, &x, &y))
68            g_MousePosition = ImVec2(x, y);
69        break;
70    }
71    case GDK_BUTTON_PRESS:
72    case GDK_BUTTON_RELEASE:
73    {
74        guint button = 0;
75        if (gdk_event_get_button(event, &button) && button > 0 && button <= 5)
76        {
77            if (type == GDK_BUTTON_PRESS)
78                g_MousePressed[button - 1] = true;
79        }
80        break;
81    }
82    case GDK_SCROLL:
83    {
84        gdouble x, y;
85        if (gdk_event_get_scroll_deltas(event, &x, &y))
86            g_MouseWheel = -y;
87        break;
88    }
89    case GDK_KEY_PRESS:
90    case GDK_KEY_RELEASE:
91    {
92        GdkEventKey *e = (GdkEventKey *) event;
93
94        static const struct
95        {
96            enum ImGuiKey_ imgui;
97            guint gdk;
98        } gdk_key_to_imgui_key[] =
99              {
100                  { ImGuiKey_Tab, GDK_KEY_Tab },
101                  { ImGuiKey_Tab, GDK_KEY_ISO_Left_Tab },
102                  { ImGuiKey_LeftArrow, GDK_KEY_Left },
103                  { ImGuiKey_RightArrow, GDK_KEY_Right },
104                  { ImGuiKey_UpArrow, GDK_KEY_Up },
105                  { ImGuiKey_DownArrow, GDK_KEY_Down },
106                  { ImGuiKey_PageUp, GDK_KEY_Page_Up },
107                  { ImGuiKey_PageDown, GDK_KEY_Page_Down },
108                  { ImGuiKey_Home, GDK_KEY_Home },
109                  { ImGuiKey_End, GDK_KEY_End },
110                  { ImGuiKey_Delete, GDK_KEY_Delete },
111                  { ImGuiKey_Backspace, GDK_KEY_BackSpace },
112                  { ImGuiKey_Enter, GDK_KEY_Return },
113                  { ImGuiKey_Escape, GDK_KEY_Escape },
114                  { ImGuiKey_A, GDK_KEY_a },
115                  { ImGuiKey_C, GDK_KEY_c },
116                  { ImGuiKey_V, GDK_KEY_v },
117                  { ImGuiKey_X, GDK_KEY_x },
118                  { ImGuiKey_Y, GDK_KEY_y },
119                  { ImGuiKey_Z, GDK_KEY_z },
120              };
121        for (unsigned i = 0; i < ARRAY_SIZE(gdk_key_to_imgui_key); i++)
122        {
123            if (e->keyval == gdk_key_to_imgui_key[i].gdk)
124                io.KeysDown[gdk_key_to_imgui_key[i].imgui] = type == GDK_KEY_PRESS;
125        }
126        gunichar c = gdk_keyval_to_unicode(e->keyval);
127        if (g_unichar_isprint(c) && ImGuiKey_COUNT + c < ARRAY_SIZE(io.KeysDown))
128            io.KeysDown[ImGuiKey_COUNT + c] = type == GDK_KEY_PRESS;
129
130        if (type == GDK_KEY_PRESS && e->string)
131            io.AddInputCharactersUTF8(e->string);
132
133        struct {
134            bool *var;
135            GdkModifierType modifier;
136            guint keyvals[3];
137        } mods[] = {
138            { &io.KeyCtrl, GDK_CONTROL_MASK,
139              { GDK_KEY_Control_L, GDK_KEY_Control_R, 0 }, },
140            { &io.KeyShift, GDK_SHIFT_MASK,
141              { GDK_KEY_Shift_L, GDK_KEY_Shift_R, 0 }, },
142            { &io.KeyAlt, GDK_MOD1_MASK,
143              { GDK_KEY_Alt_L, GDK_KEY_Alt_R, 0 }, },
144            { &io.KeySuper, GDK_SUPER_MASK,
145              { GDK_KEY_Super_L, GDK_KEY_Super_R, 0 }, }
146        };
147        for (unsigned i = 0; i < ARRAY_SIZE(mods); i++)
148        {
149            *mods[i].var = (mods[i].modifier & e->state);
150
151            bool match = false;
152            for (int j = 0; mods[i].keyvals[j] != 0; j++)
153                if (e->keyval == mods[i].keyvals[j])
154                    match = true;
155
156            if (match)
157                *mods[i].var = type == GDK_KEY_PRESS;
158        }
159        break;
160    }
161    default:
162        break;
163    }
164
165    // We trigger 2 subsequent redraws for each event because of the
166    // way some ImGui widgets work. For example a Popup menu will only
167    // appear a frame after a click happened.
168    g_NumRedraws = 2;
169
170    gtk_widget_queue_draw(g_GtkGlArea);
171}
172
173static gboolean handle_gdk_event(GtkWidget *widget, GdkEvent *event, void *data)
174{
175    ImGui_ImplGtk3_HandleEvent(event);
176    return TRUE;
177}
178
179bool ImGui_ImplGtk3_Init(GtkWidget* gl_area, bool install_callbacks)
180{
181    g_clear_pointer(&g_GtkGlArea, g_object_unref);
182
183    g_GtkGlArea = GTK_WIDGET(g_object_ref(gl_area));
184    gtk_widget_realize(g_GtkGlArea);
185    gtk_widget_set_can_focus(g_GtkGlArea, TRUE);
186    gtk_widget_grab_focus(g_GtkGlArea);
187
188    if (install_callbacks) {
189        gtk_widget_add_events(g_GtkGlArea, EVENT_MASK);
190        g_signal_connect(g_GtkGlArea, "event", G_CALLBACK(handle_gdk_event), NULL);
191    }
192
193    ImGuiIO& io = ImGui::GetIO();
194    for (int i = 0; i < ImGuiKey_COUNT; i++)
195    {
196        io.KeyMap[i] = i;
197    }
198
199    io.SetClipboardTextFn = ImGui_ImplGtk3_SetClipboardText;
200    io.GetClipboardTextFn = ImGui_ImplGtk3_GetClipboardText;
201    io.ClipboardUserData = gtk_widget_get_clipboard(g_GtkGlArea,
202                                                    GDK_SELECTION_CLIPBOARD);
203
204    return true;
205}
206
207void ImGui_ImplGtk3_Shutdown()
208{
209    g_clear_pointer(&g_GtkGlArea, g_object_unref);
210    if (g_RedrawTimeout)
211        g_source_remove(g_RedrawTimeout);
212}
213
214static gboolean timeout_callback(gpointer data)
215{
216    gtk_widget_queue_draw(g_GtkGlArea);
217    g_RedrawTimeout = 0;
218    return FALSE;
219}
220
221static void kick_timeout_redraw(float timeout)
222{
223    if (g_RedrawTimeout)
224        return;
225    g_RedrawTimeout = g_timeout_add(timeout * 1000, timeout_callback, NULL);
226}
227
228void ImGui_ImplGtk3_NewFrame()
229{
230    bool next_redraw = false;
231    if (g_NumRedraws > 0)
232    {
233        gtk_widget_queue_draw(g_GtkGlArea);
234        g_NumRedraws--;
235        next_redraw = true;
236    }
237
238    ImGuiIO& io = ImGui::GetIO();
239
240    // Setup display size (every frame to accommodate for window resizing)
241    io.DisplaySize = ImVec2((float)gtk_widget_get_allocated_width(g_GtkGlArea),
242                            (float)gtk_widget_get_allocated_height(g_GtkGlArea));
243    int scale_factor = gtk_widget_get_scale_factor(g_GtkGlArea);
244    io.DisplayFramebufferScale = ImVec2(scale_factor, scale_factor);
245
246    // Setup time step
247    guint64 current_time =  g_get_monotonic_time();
248    io.DeltaTime = g_Time > 0 ? ((float)(current_time - g_Time) / 1000000) : (float)(1.0f/60.0f);
249    g_Time = current_time;
250
251    // Setup inputs
252    if (gtk_widget_has_focus(g_GtkGlArea))
253    {
254        io.MousePos = g_MousePosition;   // Mouse position in screen coordinates (set to -1,-1 if no mouse / on another screen, etc.)
255    }
256    else
257    {
258        io.MousePos = ImVec2(-1,-1);
259    }
260
261    GdkWindow *window = gtk_widget_get_window(g_GtkGlArea);
262    GdkDevice *pointer = gdk_device_manager_get_client_pointer(gdk_display_get_device_manager(gdk_display_get_default()));
263    GdkModifierType modifiers;
264    gdk_device_get_state(pointer, window, NULL, &modifiers);
265
266    for (int i = 0; i < 3; i++)
267    {
268        io.MouseDown[i] = g_MousePressed[i] || (modifiers & (GDK_BUTTON1_MASK << i)) != 0;
269        g_MousePressed[i] = false;
270    }
271
272    io.MouseWheel = g_MouseWheel;
273    g_MouseWheel = 0.0f;
274
275    // Hide OS mouse cursor if ImGui is drawing it
276    GdkDisplay *display = gdk_window_get_display(window);
277    GdkCursor *cursor =
278      gdk_cursor_new_from_name(display, io.MouseDrawCursor ? "none" : "default");
279    gdk_window_set_cursor(window, cursor);
280    g_object_unref(cursor);
281
282    if (!next_redraw && io.WantTextInput)
283        kick_timeout_redraw(0.2);
284}
285