PowerBuilder 11.5 supports the Portable Networks Graphics (PNG) file format for the images that you use in menus, toolbars, treeview controls, and DataWindow objects. PNG images display at design time as they do at runtime. Transparent portions of a PNG image display the background color or color gradient of the control to which they are assigned when the control has a background color or color gradient property.
In a Picture control For picture controls without a background color property, transparent portions of a PNG image display the background color of the parent object or control. For example, the PowerBuilder Picture control does not have a background color property. If you assign a transparent PNG image to the Picture control, the transparent portions display the background color of the window or object that contains the Picture control.
In a PictureButton control Unlike the Picture control, the PictureButton control does have a background color property in PowerBuilder. If you assign a transparent PNG image to the PictureButton control, it displays with the background color assigned to the PictureButton control. If you want the PNG image in a PictureButton control to blend in with the background of the container object for the PictureButton control, you must set the PictureButton’s BackColor property to the background color of its container object.
Covering other controls or images If you display a transparent PNG image in a Picture control on a window, and the Picture control covers part of a ListBox control (or other noncontainer control or object), the transparent portion of the PNG image clips the control or object it covers and displays with the background color of its container object. If the container object, such as a window, includes a background image in addition to a background color, the PNG image displays the background color only and clips any background image that it covers.
Supported target types and exceptions You can deploy PNG images with standard PowerBuilder targets and with .NET Windows Forms or Web Forms targets. However, PNG images cannot be selected in DataWindow objects with the RichText or OLE presentation style. Also, if you export a DataWindow object as a PDF file using the XSLFOP method, PNG images in the DataWindow are not saved in the generated PDF. PNG images with transparency settings are fully supported in Internet Explorer 7.0 browsers, but earlier versions of the browser cannot display the transparency effects of these images.
PNG images are drawn with GDI+ functions rather than with bitmap functions. Therefore the Map3DColors property for Picture and PictureButton controls is ignored when you select a PNG file for the picture image. PNG images are also kept locked while the image is active. This is in contrast to bitmap images, which are released once the image is loaded.
