Omnis Externals

ImageLib Documentation

Am Image processing utility external for use with Omnis Studio

• character[] $versionInfo(): returns a character array containing the control string: " ImageLib version: MAJOR_VERSION_NUMBER . MINOR_VERSION_NUMBER ".
• character[] $demoInfo(): returns a character array containing a string to indicate, where appropriate, if the external has compiled as a demo version and the expiry date of the demo.
• void $clearLastError(): Clears the contents of the current error message
• character[] $getLastError(): Returns a string describing the last detected error
• bool[] $hasregisterederror(): returns a boolean indicating presence of current error message

• bool[] $readfile( character[] ): accepts path of source image file and returns a boolean indicating success of readfile operation.
• bool[] $writefile( character[] ): accepts path of target image file, writes the image to file and returns a boolean indicating success of file write operation.
• integer[] $filesize(): Returns size (in bytes) of an initialised image
• bin[] $getas( character[] ): accepts string describing desired image format (e.g. "JPG") and returns a copy of the image as a binary blob in specified format
• bool[] $crop( character[] ): accepts a geometry string (see below), crops an image (extracts a sub-image) of the desired width and height, applying offsets if desired and returns boolean to indicate success or failure
• bool[] $chop( character[] ): accepts a geometry string (see below), chops an image (removes a sub-image) of the desired width and height, applying offsets if desired and returns boolean to indicate success or failure
• integer[] $columns(): Returns the number of columns (pixel width) in this image
• integer[] $rows(): Returns the number of rows (pixel height) in this image
• bool[] $setfrom( binary[] ): accepts a binary blob containing an image in a supported format, Initialises this image using the binary blob and returns a boolean indicating success or failure.
• integer[] $getdepth(): Returns the colour depth of the image (8 or 16 bits)
• bool[] $setdepth( integer[] ): accepts an integer of value equal to the desired depth, sets the colour depth of the image (to 8 or 16 bits) and returns a boolean indicating success or failure.
• bool[] $sample( character[] ): accepts an extended geometry string indicating the desired height, width of the output along with any optional flags (e.g. <,>,!,% - see geometry strings), resizes the image, using a pixel sampling algorithm, and returns boolean indicating success or failure. This method performs interpolation and will give better quality results than the $scale method.
• bool[] $scale( character[] ): accepts an extended geometry string indicating the desired height, width of the output along with any optional flags (e.g. <,>,!,% - see geometry strings), resizes the image, using a simple ratio algorithm, and returns boolean indicating success or failure.
• bool[] $rotate( real[] ): accepts a real number indicating the desired angle of rotation (in degrees), Rotates the pixels within the image canvas and returns a boolean indicating success or failure.
• bool[] $quality( integer[] ): accepts an integer specifying the desired quality, adjusts the output quality of images for those formats that support this operation //(JPG, MIFF and PNG). The permitted range is [0,100] with a default value of 75. Returns a boolean indicating success or failure.
• bool[] $isvalid():Describes whether the image object is in a valid (viewable) state or not. Returns a boolean describing the state of the object

Geometry strings are of the format: "<width>x<height>{+-}<xoffset>{+-}<yoffset>"

Extended geometry strings are of the format: "<width>x<height>{+-}<xoffset>{+-}<yoffset>{%}{!}{<}{>}"

where geometry qualifiers indicate the following: