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Scalable Image

Scalable Image is a widget capable of drawing a scaled version of a bitmap. Simply change the width/height of the widget to resize the image. The quality of the scaled image depends of the rendering algorithm used. The rendering algorithm can be changed dynamically.

  • This widget has a significant effect on the MCU load.
  • This widget does not support 1 bit per pixel color depth.
  • Scalable Image running in the simulator

    Widget Group

    The Scalable Image can be found in the Images widget group in TouchGFX Designer.

    Scalable Image in TouchGFX Designer


    The properties for a Scalable Image in TouchGFX Designer.

    Property GroupProperty Descriptions
    NameName of the widget. Name is the unique identifier used in TouchGFX Designer and code.
    LocationX and Y specify the top left corner of the widget relative to its parent.

    W and H specify the width and height of the widget.

    Lock specifies if the widget should be locked in its current X, Y, W and H.
    Locking the widget also disables interacting with the widget through the screen.

    Visible specifies the visibility of the widget. Making the widget invisible also disables interacting with the widget through the screen.
    ImageScaling Algorithm specifies the algorithm used for scaling the chosen image.

    Image specifies which image the widget should use.
    AppearanceAlpha specifies the transparency of the widget. The alpha value ranges between 0 and 255 for the widget. 0 is fully transparent and 255 is solid.
    MixinsDraggable specifies if the widget is draggable at runtime.

    ClickListener specifies if the widget emits a callback when clicked.

    FadeAnimator specifies if the widget can animate changes to its Alpha value.

    MoveAnimator specifies if the widget can animate changes to X and Y values.


    The actions and triggers supported by a Scalable Image in TouchGFX Designer.


    Widget specific actionDescription
    Resize widgetResize the width and height of a widget.
    Standard widget actionDescription
    Move widgetMove a widget to a new position over time.
    Fade widgetModify alpha value of widget over time.
    Hide widgetHides a widget (sets visibility to false).
    Show widgetMake a hidden widget visible (sets visibility to true).


    A Scalable Image does not emit any triggers.


    A Scalable Image heavily depends upon the MCU for scaling the image. Therefore, the Scalable Image is considered a demanding widget on most platforms.

    For more details on drawing performance, read the read the General UI Component Performance section.


    Generated Code

    In the generated code for the View base class we can see how the Designer sets up a Scalable Image.

    #include <gui_generated/screen1_screen/Screen1ViewBase.hpp>
    #include "BitmapDatabase.hpp"

    scalableImage.setPosition(246, 36, 200, 200);


    void Screen1ViewBase::setupScreen()

    You can use these functions and the others available in the ScalableImage class in user code. Remember to force a redraw by calling scalableImage.invalidate() if you change the appearance of the widget.

    TouchGFX Designer Examples

    To further explore the Scalable Image, try creating a new application within TouchGFX Designer with one of the following UI templates:

    Scale and Zoom Example UI template in TouchGFX Designer

    API Reference