GLArea

gtk.glarea.GLArea is a widget that allows drawing with OpenGL.

An example GtkGLArea

gtk.glarea.GLArea sets up its own gdk.glcontext.GLContext, and creates a custom GL framebuffer that the widget will do GL rendering onto. It also ensures that this framebuffer is the default GL rendering target when rendering. The completed rendering is integrated into the larger GTK scene graph as a texture.

In order to draw, you have to connect to the gtk.glarea.GLArea.render signal, or subclass gtk.glarea.GLArea and override the GtkGLAreaClass.render virtual function.

The gtk.glarea.GLArea widget ensures that the gdk.glcontext.GLContext is associated with the widget's drawing area, and it is kept updated when the size and position of the drawing area changes.

Drawing with GtkGLArea

The simplest way to draw using OpenGL commands in a gtk.glarea.GLArea is to create a widget instance and connect to the gtk.glarea.GLArea.render signal:

The render() function will be called when the gtk.glarea.GLArea is ready for you to draw its content:

The initial contents of the framebuffer are transparent.

static gboolean
render (GtkGLArea *area, GdkGLContext *context)
{
  // inside this function it's safe to use GL; the given
  // GdkGLContext has been made current to the drawable
  // surface used by the `GtkGLArea` and the viewport has
  // already been set to be the size of the allocation

  // we can start by clearing the buffer
  glClearColor (0, 0, 0, 0);
  glClear (GL_COLOR_BUFFER_BIT);

  // draw your object
  // draw_an_object ();

  // we completed our drawing; the draw commands will be
  // flushed at the end of the signal emission chain, and
  // the buffers will be drawn on the window
  return TRUE;
}

void setup_glarea (void)
{
  // create a GtkGLArea instance
  GtkWidget *gl_area = gtk_gl_area_new ();

  // connect to the "render" signal
  g_signal_connect (gl_area, "render", G_CALLBACK (render), NULL);
}

If you need to initialize OpenGL state, e.g. buffer objects or shaders, you should use the gtk.widget.Widget.realize signal; you can use the gtk.widget.Widget.unrealize signal to clean up. Since the gdk.glcontext.GLContext creation and initialization may fail, you will need to check for errors, using gtk.glarea.GLArea.getError.

An example of how to safely initialize the GL state is:

static void
on_realize (GtkGLarea *area)
{
  // We need to make the context current if we want to
  // call GL API
  gtk_gl_area_make_current (area);

  // If there were errors during the initialization or
  // when trying to make the context current, this
  // function will return a GError for you to catch
  if (gtk_gl_area_get_error (area) != NULL)
    return;

  // You can also use gtk_gl_area_set_error() in order
  // to show eventual initialization errors on the
  // GtkGLArea widget itself
  GError *internal_error = NULL;
  init_buffer_objects (&error);
  if (error != NULL)
    {
      gtk_gl_area_set_error (area, error);
      g_error_free (error);
      return;
    }

  init_shaders (&error);
  if (error != NULL)
    {
      gtk_gl_area_set_error (area, error);
      g_error_free (error);
      return;
    }
}

If you need to change the options for creating the gdk.glcontext.GLContext you should use the signal@Gtk.GLArea::create-context signal.

Constructors

this this(): Creates a new gtk.glarea.GLArea widget.

Members

Functions

attachBuffers void attachBuffers(): Binds buffers to the framebuffer.
connectCreateContext ulong connectCreateContext(T callback, Flag!"After" after): Connect to CreateContext signal.
connectRender ulong connectRender(T callback, Flag!"After" after): Connect to Render signal.
connectResize ulong connectResize(T callback, Flag!"After" after): Connect to Resize signal.
getAllowedApis gdk.types.GLAPI getAllowedApis(): Gets the allowed APIs.
getApi gdk.types.GLAPI getApi(): Gets the API that is currently in use.
getAutoRender bool getAutoRender(): Returns whether the area is in auto render mode or not.
getContext gdk.glcontext.GLContext getContext(): Retrieves the gdk.glcontext.GLContext used by area.
getError glib.error.ErrorG getError(): Gets the current error set on the area.
getHasDepthBuffer bool getHasDepthBuffer(): Returns whether the area has a depth buffer.
getHasStencilBuffer bool getHasStencilBuffer(): Returns whether the area has a stencil buffer.
getRequiredVersion void getRequiredVersion(int major, int minor): Retrieves the required version of OpenGL.
getUseEs bool getUseEs(): Returns whether the gtk.glarea.GLArea should use OpenGL ES.
makeCurrent void makeCurrent(): Ensures that the gdk.glcontext.GLContext used by area is associated with the gtk.glarea.GLArea.
queueRender void queueRender(): Marks the currently rendered data (if any) as invalid, and queues a redraw of the widget.
setAllowedApis void setAllowedApis(gdk.types.GLAPI apis): Sets the allowed APIs to create a context with.
setAutoRender void setAutoRender(bool autoRender): Sets whether the gtk.glarea.GLArea is in auto render mode.
setError void setError(glib.error.ErrorG error): Sets an error on the area which will be shown instead of the GL rendering.
setHasDepthBuffer void setHasDepthBuffer(bool hasDepthBuffer): Sets whether the gtk.glarea.GLArea should use a depth buffer.
setHasStencilBuffer void setHasStencilBuffer(bool hasStencilBuffer): Sets whether the gtk.glarea.GLArea should use a stencil buffer.
setRequiredVersion void setRequiredVersion(int major, int minor): Sets the required version of OpenGL to be used when creating the context for the widget.
setUseEs void setUseEs(bool useEs): Sets whether the area should create an OpenGL or an OpenGL ES context.

Inherited Members

getDefaultDirection gtk.types.TextDirection getDefaultDirection(): Obtains the current default reading direction.
setDefaultDirection void setDefaultDirection(gtk.types.TextDirection dir): Sets the default reading direction for widgets.
actionSetEnabled void actionSetEnabled(string actionName, bool enabled): Enable or disable an action installed with gtk.widget_class.WidgetClass.installAction.
activate bool activate(): For widgets that can be “activated” (buttons, menu items, etc.), this function activates them.
activateAction bool activateAction(string name, glib.variant.VariantG args): Looks up the action in the action groups associated with widget and its ancestors, and activates it.
activateDefault void activateDefault(): Activates the default.activate action from widget.
addController void addController(gtk.event_controller.EventController controller): Adds controller to widget so that it will receive events.
addCssClass void addCssClass(string cssClass): Adds a style class to widget.
addMnemonicLabel void addMnemonicLabel(gtk.widget.Widget label): Adds a widget to the list of mnemonic labels for this widget.
addTickCallback uint addTickCallback(gtk.types.TickCallback callback): Queues an animation frame update and adds a callback to be called before each frame.
allocate void allocate(int width, int height, int baseline, gsk.transform.Transform transform): This function is only used by gtk.widget.Widget subclasses, to assign a size, position and (optionally) baseline to their child widgets.
childFocus bool childFocus(gtk.types.DirectionType direction): Called by widgets as the user moves around the window using keyboard shortcuts.
computeBounds bool computeBounds(gtk.widget.Widget target, graphene.rect.Rect outBounds): Computes the bounds for widget in the coordinate space of target.
computeExpand bool computeExpand(gtk.types.Orientation orientation): Computes whether a container should give this widget extra space when possible.
computePoint bool computePoint(gtk.widget.Widget target, graphene.point.Point point, graphene.point.Point outPoint): Translates the given point in widget's coordinates to coordinates relative to target’s coordinate system.
computeTransform bool computeTransform(gtk.widget.Widget target, graphene.matrix.Matrix outTransform): Computes a matrix suitable to describe a transformation from widget's coordinate system into target's coordinate system.
contains bool contains(double x, double y): Tests if the point at (x, y) is contained in widget.
createPangoContext pango.context.Context createPangoContext(): Creates a new pango.context.Context with the appropriate font map, font options, font description, and base direction for drawing text for this widget.
createPangoLayout pango.layout.Layout createPangoLayout(string text): Creates a new pango.layout.Layout with the appropriate font map, font description, and base direction for drawing text for this widget.
disposeTemplate void disposeTemplate(gobject.types.GType widgetType): Clears the template children for the given widget.
dragCheckThreshold bool dragCheckThreshold(int startX, int startY, int currentX, int currentY): Checks to see if a drag movement has passed the GTK drag threshold.
errorBell void errorBell(): Notifies the user about an input-related error on this widget.
getAllocatedBaseline int getAllocatedBaseline(): Returns the baseline that has currently been allocated to widget.
getAllocatedHeight int getAllocatedHeight(): Returns the height that has currently been allocated to widget.
getAllocatedWidth int getAllocatedWidth(): Returns the width that has currently been allocated to widget.
getAncestor gtk.widget.Widget getAncestor(gobject.types.GType widgetType): Gets the first ancestor of widget with type widget_type.
getBaseline int getBaseline(): Returns the baseline that has currently been allocated to widget.
getCanFocus bool getCanFocus(): Determines whether the input focus can enter widget or any of its children.
getCanTarget bool getCanTarget(): Queries whether widget can be the target of pointer events.
getChildVisible bool getChildVisible(): Gets the value set with gtk.widget.Widget.setChildVisible.
getClipboard gdk.clipboard.Clipboard getClipboard(): Gets the clipboard object for widget.
getColor void getColor(gdk.rgba.RGBA color): Gets the current foreground color for the widget’s CSS style.
getCssClasses string[] getCssClasses(): Returns the list of style classes applied to widget.
getCssName string getCssName(): Returns the CSS name that is used for self.
getCursor gdk.cursor.Cursor getCursor(): Queries the cursor set on widget.
getDirection gtk.types.TextDirection getDirection(): Gets the reading direction for a particular widget.
getDisplay gdk.display.Display getDisplay(): Get the gdk.display.Display for the toplevel window associated with this widget.
getFirstChild gtk.widget.Widget getFirstChild(): Returns the widget’s first child.
getFocusChild gtk.widget.Widget getFocusChild(): Returns the current focus child of widget.
getFocusOnClick bool getFocusOnClick(): Returns whether the widget should grab focus when it is clicked with the mouse.
getFocusable bool getFocusable(): Determines whether widget can own the input focus.
getFontMap pango.font_map.FontMap getFontMap(): Gets the font map of widget.
getFontOptions cairo.font_options.FontOptions getFontOptions(): Returns the cairo.font_options.FontOptions of widget.
getFrameClock gdk.frame_clock.FrameClock getFrameClock(): Obtains the frame clock for a widget.
getHalign gtk.types.Align getHalign(): Gets the horizontal alignment of widget.
getHasTooltip bool getHasTooltip(): Returns the current value of the has-tooltip property.
getHeight int getHeight(): Returns the content height of the widget.
getHexpand bool getHexpand(): Gets whether the widget would like any available extra horizontal space.
getHexpandSet bool getHexpandSet(): Gets whether gtk.widget.Widget.setHexpand has been used to explicitly set the expand flag on this widget.
getLastChild gtk.widget.Widget getLastChild(): Returns the widget’s last child.
getLayoutManager gtk.layout_manager.LayoutManager getLayoutManager(): Retrieves the layout manager used by widget.
getMapped bool getMapped(): Whether the widget is mapped.
getMarginBottom int getMarginBottom(): Gets the bottom margin of widget.
getMarginEnd int getMarginEnd(): Gets the end margin of widget.
getMarginStart int getMarginStart(): Gets the start margin of widget.
getMarginTop int getMarginTop(): Gets the top margin of widget.
getName string getName(): Retrieves the name of a widget.
getNative gtk.native.Native getNative(): Returns the nearest gtk.native.Native ancestor of widget.
getNextSibling gtk.widget.Widget getNextSibling(): Returns the widget’s next sibling.
getOpacity double getOpacity(): #Fetches the requested opacity for this widget.
getOverflow gtk.types.Overflow getOverflow(): Returns the widget’s overflow value.
getPangoContext pango.context.Context getPangoContext(): Gets a pango.context.Context with the appropriate font map, font description, and base direction for this widget.
getParent gtk.widget.Widget getParent(): Returns the parent widget of widget.
getPreferredSize void getPreferredSize(gtk.requisition.Requisition minimumSize, gtk.requisition.Requisition naturalSize): Retrieves the minimum and natural size of a widget, taking into account the widget’s preference for height-for-width management.
getPrevSibling gtk.widget.Widget getPrevSibling(): Returns the widget’s previous sibling.
getPrimaryClipboard gdk.clipboard.Clipboard getPrimaryClipboard(): Gets the primary clipboard of widget.
getRealized bool getRealized(): Determines whether widget is realized.
getReceivesDefault bool getReceivesDefault(): Determines whether widget is always treated as the default widget within its toplevel when it has the focus, even if another widget is the default.
getRequestMode gtk.types.SizeRequestMode getRequestMode(): Gets whether the widget prefers a height-for-width layout or a width-for-height layout.
getRoot gtk.root.Root getRoot(): Returns the gtk.root.Root widget of widget.
getScaleFactor int getScaleFactor(): Retrieves the internal scale factor that maps from window coordinates to the actual device pixels.
getSensitive bool getSensitive(): Returns the widget’s sensitivity.
getSettings gtk.settings.Settings getSettings(): Gets the settings object holding the settings used for this widget.
getSize int getSize(gtk.types.Orientation orientation): Returns the content width or height of the widget.
getSizeRequest void getSizeRequest(int width, int height): Gets the size request that was explicitly set for the widget using gtk.widget.Widget.setSizeRequest.
getStateFlags gtk.types.StateFlags getStateFlags(): Returns the widget state as a flag set.
getStyleContext gtk.style_context.StyleContext getStyleContext(): Returns the style context associated to widget.
getTemplateChild gobject.object.ObjectG getTemplateChild(gobject.types.GType widgetType, string name): Fetch an object build from the template XML for widget_type in this widget instance.
getTooltipMarkup string getTooltipMarkup(): Gets the contents of the tooltip for widget.
getTooltipText string getTooltipText(): Gets the contents of the tooltip for widget.
getValign gtk.types.Align getValign(): Gets the vertical alignment of widget.
getVexpand bool getVexpand(): Gets whether the widget would like any available extra vertical space.
getVexpandSet bool getVexpandSet(): Gets whether gtk.widget.Widget.setVexpand has been used to explicitly set the expand flag on this widget.
getVisible bool getVisible(): Determines whether the widget is visible.
getWidth int getWidth(): Returns the content width of the widget.
grabFocus bool grabFocus(): Causes widget to have the keyboard focus for the gtk.window.Window it's inside.
hasCssClass bool hasCssClass(string cssClass): Returns whether css_class is currently applied to widget.
hasDefault bool hasDefault(): Determines whether widget is the current default widget within its toplevel.
hasFocus bool hasFocus(): Determines if the widget has the global input focus.
hasVisibleFocus bool hasVisibleFocus(): Determines if the widget should show a visible indication that it has the global input focus.
hide void hide(): Reverses the effects of gtk.widget.Widget.show.
inDestruction bool inDestruction(): Returns whether the widget is currently being destroyed.
initTemplate void initTemplate(): Creates and initializes child widgets defined in templates.
insertActionGroup void insertActionGroup(string name, gio.action_group.ActionGroup group): Inserts group into widget.
insertAfter void insertAfter(gtk.widget.Widget parent, gtk.widget.Widget previousSibling): Inserts widget into the child widget list of parent.
insertBefore void insertBefore(gtk.widget.Widget parent, gtk.widget.Widget nextSibling): Inserts widget into the child widget list of parent.
isAncestor bool isAncestor(gtk.widget.Widget ancestor): Determines whether widget is somewhere inside ancestor, possibly with intermediate containers.
isDrawable bool isDrawable(): Determines whether widget can be drawn to.
isFocus bool isFocus(): Determines if the widget is the focus widget within its toplevel.
isSensitive bool isSensitive(): Returns the widget’s effective sensitivity.
isVisible bool isVisible(): Determines whether the widget and all its parents are marked as visible.
keynavFailed bool keynavFailed(gtk.types.DirectionType direction): Emits the ::keynav-failed signal on the widget.
listMnemonicLabels gtk.widget.Widget[] listMnemonicLabels(): Returns the widgets for which this widget is the target of a mnemonic.
map void map(): Causes a widget to be mapped if it isn’t already.
measure void measure(gtk.types.Orientation orientation, int forSize, int minimum, int natural, int minimumBaseline, int naturalBaseline): Measures widget in the orientation orientation and for the given for_size.
mnemonicActivate bool mnemonicActivate(bool groupCycling): Emits the ::mnemonic-activate signal.
observeChildren gio.list_model.ListModel observeChildren(): Returns a gio.list_model.ListModel to track the children of widget.
observeControllers gio.list_model.ListModel observeControllers(): Returns a gio.list_model.ListModel to track the gtk.event_controller.EventControllers of widget.
pick gtk.widget.Widget pick(double x, double y, gtk.types.PickFlags flags): Finds the descendant of widget closest to the point (x, y).
queueAllocate void queueAllocate(): Flags the widget for a rerun of the vfuncGtk.Widget.size_allocate function.
queueDraw void queueDraw(): Schedules this widget to be redrawn in the paint phase of the current or the next frame.
queueResize void queueResize(): Flags a widget to have its size renegotiated.
realize void realize(): Creates the GDK resources associated with a widget.
removeController void removeController(gtk.event_controller.EventController controller): Removes controller from widget, so that it doesn't process events anymore.
removeCssClass void removeCssClass(string cssClass): Removes a style from widget.
removeMnemonicLabel void removeMnemonicLabel(gtk.widget.Widget label): Removes a widget from the list of mnemonic labels for this widget.
removeTickCallback void removeTickCallback(uint id): Removes a tick callback previously registered with gtk.widget.Widget.addTickCallback.
setCanFocus void setCanFocus(bool canFocus): Specifies whether the input focus can enter the widget or any of its children.
setCanTarget void setCanTarget(bool canTarget): Sets whether widget can be the target of pointer events.
setChildVisible void setChildVisible(bool childVisible): Sets whether widget should be mapped along with its parent.
setCssClasses void setCssClasses(string[] classes): Clear all style classes applied to widget and replace them with classes.
setCursor void setCursor(gdk.cursor.Cursor cursor): Sets the cursor to be shown when pointer devices point towards widget.
setCursorFromName void setCursorFromName(string name): Sets a named cursor to be shown when pointer devices point towards widget.
setDirection void setDirection(gtk.types.TextDirection dir): Sets the reading direction on a particular widget.
setFocusChild void setFocusChild(gtk.widget.Widget child): Set child as the current focus child of widget.
setFocusOnClick void setFocusOnClick(bool focusOnClick): Sets whether the widget should grab focus when it is clicked with the mouse.
setFocusable void setFocusable(bool focusable): Specifies whether widget can own the input focus.
setFontMap void setFontMap(pango.font_map.FontMap fontMap): Sets the font map to use for Pango rendering.
setFontOptions void setFontOptions(cairo.font_options.FontOptions options): Sets the cairo.font_options.FontOptions used for Pango rendering in this widget.
setHalign void setHalign(gtk.types.Align align_): Sets the horizontal alignment of widget.
setHasTooltip void setHasTooltip(bool hasTooltip): Sets the has-tooltip property on widget to has_tooltip.
setHexpand void setHexpand(bool expand): Sets whether the widget would like any available extra horizontal space.
setHexpandSet void setHexpandSet(bool set): Sets whether the hexpand flag will be used.
setLayoutManager void setLayoutManager(gtk.layout_manager.LayoutManager layoutManager): Sets the layout manager delegate instance that provides an implementation for measuring and allocating the children of widget.
setMarginBottom void setMarginBottom(int margin): Sets the bottom margin of widget.
setMarginEnd void setMarginEnd(int margin): Sets the end margin of widget.
setMarginStart void setMarginStart(int margin): Sets the start margin of widget.
setMarginTop void setMarginTop(int margin): Sets the top margin of widget.
setName void setName(string name): Sets a widgets name.
setOpacity void setOpacity(double opacity): Request the widget to be rendered partially transparent.
setOverflow void setOverflow(gtk.types.Overflow overflow): Sets how widget treats content that is drawn outside the widget's content area.
setParent void setParent(gtk.widget.Widget parent): Sets parent as the parent widget of widget.
setReceivesDefault void setReceivesDefault(bool receivesDefault): Specifies whether widget will be treated as the default widget within its toplevel when it has the focus, even if another widget is the default.
setSensitive void setSensitive(bool sensitive): Sets the sensitivity of a widget.
setSizeRequest void setSizeRequest(int width, int height): Sets the minimum size of a widget.
setStateFlags void setStateFlags(gtk.types.StateFlags flags, bool clear): Turns on flag values in the current widget state.
setTooltipMarkup void setTooltipMarkup(string markup): Sets markup as the contents of the tooltip, which is marked up with Pango markup.
setTooltipText void setTooltipText(string text): Sets text as the contents of the tooltip.
setValign void setValign(gtk.types.Align align_): Sets the vertical alignment of widget.
setVexpand void setVexpand(bool expand): Sets whether the widget would like any available extra vertical space.
setVexpandSet void setVexpandSet(bool set): Sets whether the vexpand flag will be used.
setVisible void setVisible(bool visible): Sets the visibility state of widget.
shouldLayout bool shouldLayout(): Returns whether widget should contribute to the measuring and allocation of its parent.
show void show(): Flags a widget to be displayed.
snapshotChild void snapshotChild(gtk.widget.Widget child, gtk.snapshot.Snapshot snapshot): Snapshot the a child of widget.
translateCoordinates bool translateCoordinates(gtk.widget.Widget destWidget, double srcX, double srcY, double destX, double destY): Translate coordinates relative to src_widget’s allocation to coordinates relative to dest_widget’s allocations.
triggerTooltipQuery void triggerTooltipQuery(): Triggers a tooltip query on the display where the toplevel of widget is located.
unmap void unmap(): Causes a widget to be unmapped if it’s currently mapped.
unparent void unparent(): Dissociate widget from its parent.
unrealize void unrealize(): Causes a widget to be unrealized (frees all GDK resources associated with the widget).
unsetStateFlags void unsetStateFlags(gtk.types.StateFlags flags): Turns off flag values for the current widget state.
connectDestroy ulong connectDestroy(T callback, Flag!"After" after): Connect to Destroy signal.
connectDirectionChanged ulong connectDirectionChanged(T callback, Flag!"After" after): Connect to DirectionChanged signal.
connectHide ulong connectHide(T callback, Flag!"After" after): Connect to Hide signal.
connectKeynavFailed ulong connectKeynavFailed(T callback, Flag!"After" after): Connect to KeynavFailed signal.
connectMap ulong connectMap(T callback, Flag!"After" after): Connect to Map signal.
connectMnemonicActivate ulong connectMnemonicActivate(T callback, Flag!"After" after): Connect to MnemonicActivate signal.
connectMoveFocus ulong connectMoveFocus(T callback, Flag!"After" after): Connect to MoveFocus signal.
connectQueryTooltip ulong connectQueryTooltip(T callback, Flag!"After" after): Connect to QueryTooltip signal.
connectRealize ulong connectRealize(T callback, Flag!"After" after): Connect to Realize signal.
connectShow ulong connectShow(T callback, Flag!"After" after): Connect to Show signal.
connectStateFlagsChanged ulong connectStateFlagsChanged(T callback, Flag!"After" after): Connect to StateFlagsChanged signal.
connectUnmap ulong connectUnmap(T callback, Flag!"After" after): Connect to Unmap signal.
connectUnrealize ulong connectUnrealize(T callback, Flag!"After" after): Connect to Unrealize signal.

gtk glarea classes

GLArea