Image area

QPix provides a scrollable plug-in area for displaying disk-based images and 4D picture objects. The area includes a menu bar, a tools widget and a zoom widget.

To add a QPix area to a form, create a plug-in area object and select _QPix from the popup menu in the properties window. After the area rectangle is created, choose Advanced... from the properties palette to invoke to the area's Advanced Properties Dialog and do the initial setup of the area without writing any code. Later, in your code, you can introduce changes programmatically, using the commands described in this chapter.

Note

Offscreen buffers: QPix speeds up screen redraws by using offscreen buffers when displaying disk files. The memory occupied by offscreen buffers depends solely on pixel depth and image dimensions (the size of the image file is irrelevant), and they may require a lot of memory.

Pictures: When displaying a 4D picture, QPix allocates and maintains a copy of the picture data. If you are displaying large pictures, set the original 4D picture to null in order to preserve memory (pict := pict * 0). Another good idea is to pass local pict variables to QPix; local variables exist only within the scope of the calling method and they are automatically destroyed by 4D.

Commands

QPx_SetAreaStyle Configure the appearance of a QPix plug-in area
QPx_GetAreaStyle Get the appearance configuration of a QPix plug-in area
QPx_SetAreaParts Configure the visibility of the parts of a scrollable QPix plug-in area
QPx_GetAreaParts Get the visibility configuration of the parts of a scrollable QPix plug-in area
QPx_SetAreaTools Configure the tools of a scrollable QPix plug-in area
QPx_GetAreaTools Get the configuration of the tools of a scrollable QPix plug-in area
QPx_SetAreaFlags Configure various options of a QPix plug-in area
QPx_GetAreaFlags Get various configuration options of a QPix plug-in area
QPx_SetAreaBackgroundColor Set the background color of a QPix area
QPx_GetAreaBackgroundColor Get the background color of a QPix area
QPx_SetAreaScrollOffset Change the scroll offsets of a scrollable QPix plug-in area
QPx_GetAreaScrollOffset Get the scroll offsets of a scrollable QPix plug-in area
QPx_SetAreaCurrentTool Set the currently selected tool in a scrollable QPix plug-in area
QPx_GetAreaCurrentTool Get the currently selected tool in a scrollable QPix plug-in area
QPx_SetAreaZoomFactor Set the zoom factor of a scrollable QPix plug-in area
QPx_GetAreaZoomFactor Get the zoom factor of a scrollable QPix plug-in area
QPx_SetAreaSelection Set the selection marquee in a scrollable QPix plug-in area
QPx_GetAreaSelection Get the selection maquee of a scrollable QPix plug-in area
QPx_GetAreaCmdStatus Get the status of a QPix plug-in area command
QPx_DoAreaCommand Execute a QPix plug-in area command
QPx_CountAreaPages Get the number of pages of the image being displayed in a QPix area
QPx_GetAreaPage Get the number of the page being displayed in a QPix area
QPx_SetAreaPage Switch to a specific page of the image being displayed in a QPix area
QPx_SetAreaImageFile Display an image file in a QPix area
QPx_GetAreaImageFile Get the image file being displayed in a QPix area
QPx_SetAreaPicture Display a 4D picture in a QPix area
QPx_GetAreaPicture Get the 4D picture being displayed in a QPix area
QPx_SetAreaImporter Assign a graphics importer instance to a QPix area
QPx_GetAreaImporter Get a reference to the graphic importer used by a QPix area
QPx_CropAreaImage Crop the image in a QPix area to the current selection marquee
QPx_RotateAreaImage Rotate the image in a QPix area by a number of degrees
QPx_ResizeAreaImage Resize the image in a QPix area
QPx_FlipAreaImage Flip the image in a QPix area horizontally and/or vertically
QPx_InvertAreaImage Invert the colors of the image in a QPix area
QPx_ExportAreaImage Export the image of a QPix area to an image file
QPx_FilterAreaImage Apply a filter to the image in a QPix area
QPx_BrightnessContrastAreaImg Apply the Escape Brightness and Contrast filter to the image in a QPix area
QPx_SharpenAreaImage Apply the Sharpen filter to the image in a QPix area
QPx_BlurAreaImage Apply the Blur filter to the image in a QPix area
QPx_RGBBalanceAreaImage Apply the RGB Balance filter to the image in a QPix area
QPx_HSLBalanceAreaImage Apply the HSL-Balance filter to the image in a QPix area