QPx_CompressPicture

QPx_CompressPicture(pictVar; pictVar; pictVar; pictVar; pictVar):error
	pictVar	Picture	Picture variable
	codecType	Text	Codec type
	compQuality	Longint	Compression quality
	compDepth	Longint	Compression depth, optional
	compFlags	Longint	Compression flags, optional
	error	Longint	Error result

This command returns 4D pictures in the new, post v11, picture format. The command essentially is a shortcut for QPx_ExportPictureToBLOB followed by 4D's BLOB TO PICTURE.

The pictVar parameter initially contains the uncompressed picture. When the command completes, it will contain the compressed picture.

The codecType parameter specifies the codec (compressor component) that will do the compression. Use either a codec identifier, as returned by QPx_GetCodecList, or a file format identifier, as returned by QPx_GetExportTypes.

NOTE Codec types are internally mapped to file file format identifiers, as used in commands like QPx_ExportPicture for backwards compatibility.

The compQuality parameter specifies the quality of the compressed picture. Valid values are in the range of 0...1024. QPix defines the following constants for the compQuality parameter:

The compDepth parameter specifies color depth for the compressed image. If omitted or set to 0, QPix uses the original picture depth. Possible values for compDepth are:

The optional compFlags parameter specifies additional options. Currently, the only supported option is to display a progress dialog after a short while. To display the progress dialog, set compFlags to 1.

NOTE Not all codecs support all quality and depth values. If a codec does not support the specified values for quality or depth, it will automatically fall back to its respective default values.

NOTE To decompress a picture, compress it with the "raw " (mind the space at the end!) codec, or using QPx_RotatePicture($pict;0) or QPx_ResizePicture($pict;1;1)

Example

   // Compress a picture with the "jpeg" codec

C_LONGINT($error)
C_PICTURE($picture)

$picture:=[Images]Picture

$error:=QPx_CompressPicture ($picture;"jpeg";qpx_NormalQuality)

If ($error=qpx_noErr)
   
   [Images]Picture:=$picture
   
End if 

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