Unit 'icon' Package
[Overview][Constants][Types][Procedures and functions][Variables][Index] [#amunits]

LayoutIconA

Adapt a palette-mapped icon for display

Declaration

Source position: icon.pas line 372

function LayoutIconA(

  icon: pDiskObject;

  screen: pScreen;

  tags: pTagItem

):LongBool;

Arguments

icon

  

The icon to be remapped. This must be a palette mapped icon.

screen

  

Pointer to a screen to remap the icon for or nil to remap the icon to use the system default colour palette or something very similar to it (this means: four colours only).

tags

  

Additional rendering options. OBP_Precision

Function result

True if the icon could be remapped, False if the remapping failed for some reason. In case of of failure, icon.library will try its best to keep the icon in a presentable state, but this may fail. In case of failure, the error code can be retrieved using IoErr().

Description

This function will prepare an icon for display, either on a specific screen or using a default colour palette. It is useful only for palette mapped icons.

You must make sure that the screen you remap to does not go away while there is an icon to use its colours. For a public screen, the easiest way to guarantee this is to keep it locked (see LockPubScreen()). For custom screens, just don't close them! If you have to close the screen or need to keep your icon around until after a screen is closed, you should call LayoutIconA() with a nil screen parameter. This will release all pens the icon has allocated and remap the icon to a default set of colours. Alternatively, you can dispose of the icon via FreeDiskObject() which will also release all pens the icon has allocated, including the icon itself, of course.

Icons remapped to the global default screen (normally, that would be the Workbench screen) may get changed and remapped again during Workbench close/open transitions. To prevent this from taking place, just make sure that the Workbench screen does not close (e.g. via LockPubScreen()("Workbench")).

See also

IoErr

  

Return extra information from the system

ObtainBestPenA

  

Search for the closest color match, or allocate a new one.

ObtainBestPenA

  

Release an allocated palette entry to the free pool.

FreeDiskObject

  

Free all memory in a Workbench disk object.

GetIconTagList

  

Retrieve an icon

IconControlA

  

Set and get icon and icon.library options

LockPubScreen

  

Prevent a public screen from closing.

UnLockPubScreen

  

Release lock on a public screen.


Documentation generated on: 2021-07-30