QPix Command Reference Compression

QPx_CompressPicture

QPx_CompressPicture(pictVar; codecType; compQuality; compDepth; compFlags):error
pictVar Picture Picture variable
codecType String4 Codec type
compQuality Longint Compression quality
compDepth Longint Compression depth, optional
compFlags Longint Compression flags, optional
error Longint Error result

Compresses the image contained in a 4D picture variable.

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. For a list of available codecs, use the QPx_GetCodecList command.

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:

qpx_MinQuality 0 Minimal quality
qpx_LowQuality 256 Low quality
qpx_NormalQuality 512 Normal quality
qpx_HighQuality 768 High quality
qpx_MaxQuality 1023 Maximum quality
qpx_LosslessQuality 1024 Lossless quality

The compDepth parameter specifies color depth for the compressed image. If omitted or set to 0, QPix uses the original picture depth QuickTime determines the appropriate value for the picture (best depth). Possible values for compDepth are:

Black and white images1
Color images2, 8, 16, 24, 32
Grayscale images34 (2 bit), 36 (4-bit), 40 (8-bit)

The optional compFlags parameter specifies additional compression options. Currently, the only supported option is to display a progress dialog if the compression will take long to complete. To display the progress dialog, set the compFlags parameter to 1.

Notes

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
 

Related commands

QPx_DoCodecSettingsDialog Displays the standard compression settings dialog
QPx_GetCodecList Returns the list of available compressors/decompressors

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