Picture Coordinate Systems

The picture coordinate systems uniquely determine the position of a point or other geometric element in a picture. All coordinates used by a picture, Dynamo Set, or animation are measured in the document's coordinate system, which can be either:

• Logical
• Enhanced

Logical Coordinate System

The Logical Coordinate System is a legacy system that was used for pictures created with iFIX 5.5 or earlier. With the Logical Coordinate System, the screen resolution is measured in logical units. The logical unit value is derived from the screen resolution of the terminal on which the picture was originally created. When viewing this picture on a terminal with a different screen resolution, the picture may not automatically scale to the new screen resolution.

The Logical Coordinate System uses the following properties to identify the logical units used for the height and width of the document as displayed in the Property window.

Property	Description
DocumentHeight	Specifies the height of the document in logical units.
DocumentWidth	Specifies the width of the document in logical units.

With the Logical Coordinate System, the Auto Scale option allows you to move pictures between screens with the same resolution. However, when viewed on a screen with a different resolution, the picture many not scale as desired. When moving pictures to a screen with a different resolution, it is recommended to use the Enhanced Coordinate System.

Enhanced Coordinate System

The Enhanced Coordinate System is provided for iFIX 5.8 and greater. With the Enhanced Coordinate System, you can create a picture that provides independence from restricted screen resolution. For the Enhanced Coordinate System, the dimension and position of a picture are measured in postscript points. The Enhanced Coordinate System features automatic scaling of a picture when viewed on a screen with a resolution that is different from the screen on which the picture was originally created. Once a picture is created with the Enhanced Coordinate System, the picture retains its original aspects even when viewed on screens with different resolutions.

The Enhanced Coordinate System uses the following properties to reflect the height, width, and coordinate system of the graphic. Refer to the iFIX Automation Reference e-book for more information on these properties.

Property	Description
DocumentHeightEx	Specifies the document height in postscript points.
DocumentWidthEx	Specifies the document width in postscript points.
EnhancedCoordinates	Identifies the picture coordinate system as either -  True (Enhanced Coordinate System) or False (Logical Coordinate System).

You can upgrade a picture created with the Logical Coordinate System to the Enhanced Coordinate System. The Enhanced Coordinate System expert converts the picture from logical units to postscript points. During the upgrade process, the picture in the Logical Coordinate System is saved to a Backup folder before the picture is upgraded. This allows you to revert back to the original picture in logical units if you want to. Also, when a picture is upgraded, the icon changes to indicate the upgraded picture.  

By default, the Enhanced Coordinate System is enabled for new pictures. Existing legacy pictures remain in the Logical Coordinate System until you upgrade them to the Enhanced Coordinate System.

Zoom to Fit

The Enhanced Coordinate System provides a Zoom to Fit viewing preference that is enabled for run mode. Zoom To Fit suppresses scroll bars while allowing you to view the entire picture on your screen. The objects within the picture do not change their position and dimensions even when the picture is brought to a new screen resolution, which is different from the resolution on which the picture was developed. Zoom to Fit does not change the location of the objects/shapes within your picture, but scales the picture for viewing only. For more information on using Zoom to Fit, refer to the Selecting Zoom to Fit section.

By default, Zoom to Fit is enabled for run mode. You may wish to disable this preference for a special purpose.  To disable Zoom to Fit in run mode, for all pictures de-select the Zoom to Fit in Run mode check box on the General tab of the User Preference dialog Box. To disable this preference for a specific picture, put a script under the picture initialization code to call "ME.ZoomToFit False."  For more information on this script, refer to the ZoomToFit Method Example in the iFIX Automation Reference e-book.

NOTE: Zoom to Fit does not apply to a document that uses the Logical Coordinate System.

IMPORTANT: iFIX screens depend on the Dots Per Inch (DPI) setting of the physical display monitor and should always be at the recommended setting. Failure to do so may cause the picture to display improperly.

Button Caption Converter

The Button Caption Converter allows you to scale command button captions (text) when used in a picture with a screen resolution that is different from the resolutions in which the picture and command button caption were created. When text does not scale properly for a command button, the Button Caption Converter expert converts the caption text to scale across zoom factors and screen resolutions and places an overlay on the original command button caption. Using the Button Caption Converter expert, you can scale one, some, or all of the command button captions in a picture. This is useful when viewing pictures and text with Zoom to Fit. The Button Caption Converter expert supports the Enhanced Coordinate System only. The Button Caption Converter does not apply to a document that uses the Logical Coordinate System. For more information on using the Button Caption Converter, refer to the Converting Button Captions section.

Coordinate System Summary

The following table summarizes the characteristics of each coordinate system.

 

See Also

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