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

From Widget

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.