a5_runimagemagiccommand Function

IN THIS PAGE

Example: Resizing an Image
Example: Flipflopping Images
Example: Apply Effects to an Image
Example: Converting an Image
Example: Converting an .heic file to .jpg

Syntax

P a5_runImageMagicCommand(C fileIn ,C fileOut ,C command )

Arguments

fileInCharacter: The image file to transform. Supported file types include .pdf,.jpg, .jpeg, .bmp, and .heic.
fileOutCharacter: The filename for the transformed image.
commandCharacter: The ImageMagick command that defines the transformation. Supports options used with the ImageMagick convert tool.

Returns

resultPointer

Returns a dot variable with the following properties:

hasErrorLogical: If the operation succeeds, result.hasError will be .F..
errorTextCharacter: If the operation fails, result.errorText will contain an error message.

Description

Transforms an image using ImageMagick. Command is an ImageMagick transform command e.g. -resize 800x300

Discussion

The a5_runImageMagicCommand() function can be used to transform an image using ImageMagick. The method uses the ImageMagick "convert" tool to transform an image. You can pass in any command that is supported by the convert tool as the third argument to the function.

If an error occurs while executing the command, you can check the value of the returned dot variable to find out more information about the failure.

dim fileIn as c = "C:\temp\img.jpg"
dim fileOut as c = "C:\temp\img_resize.jpg"

dim result as p
result = a5_runImageMagicCommand(fileIn, fileOut, "-resize 20%")

if (result.hasError) then
    ' an error occurred:
    showvar(result.errorText)
end if

The examples below demonstrate using a5_runImageMagicCommand() to resize, flip, colorize, or apply interesting effects to an image.

Example: Resizing an Image

dim fileIn as c = "C:\temp\img.jpg"
dim fileOut as c = "C:\temp\img_resize.jpg"

dim result as p
' Resize image to 20% it's original size:
result = a5_runImageMagicCommand(fileIn, fileOut, "-resize 20%")

' Resize image to 500px wide. Height will be adjusted to maintain aspect ratio:
result = a5_runImageMagicCommand(fileIn, fileOut, "-resize 500")

' Resize image to 300p high. Width will be adjusted to maintain aspect ratio:
result = a5_runImageMagicCommand(fileIn, fileOut, "-resize x300")

' Resize image to 800x300 regardless of the original aspect ratio
result = a5_runImageMagicCommand(fileIn, fileOut, "-resize 800x300!")

Example: Flipflopping Images

dim fileIn as c = "C:\temp\img.jpg"

dim result as p
' Flips an image in the vertical direction:
result = a5_runImageMagicCommand(fileIn, "C:\temp\img_flip.jpg", "-flip")

' Flops an image in the horizontal direction:
result = a5_runImageMagicCommand(fileIn, "C:\temp\img_flop.jpg", "-flop")

Example: Apply Effects to an Image

dim fileIn as c = "C:\temp\img.jpg"

dim result as p
' Convert the image to black & white:
result = a5_runImageMagicCommand(fileIn, "C:\temp\img_blackAndWhite.jpg", "-monochrome")

' Convert the image to Sepia tones:
result = a5_runImageMagicCommand(fileIn, "C:\temp\img_sepia.jpg", "-sepia-tone 80%")

' Apply a vignette effect:
result = a5_runImageMagicCommand(fileIn, "C:\temp\img_vignette.jpg", "-vignette 100x65000")

Example: Converting an Image

See Supported Image Formats for a list of supported types by ImageMagick.

dim fin as c = "C:\temp\image.tiff"
dim fout as c = "C:\temp\image.pdf"

? a5_runimagemagiccommand(fin, fout, "")
= errorText = ""
hasError = .F.

Example: Converting an .heic file to .jpg

dim fileIn as c = "C:\data\img.heic"
dim fileOut as c = "C:\data\img_resize.jpg"
dim result as p
result = a5_runImageMagicCommand(fileIn, fileOut, "-resize 20%")

if (result.hasError) then
    ' an error occurred:
    showvar(result.errorText)
end if

For more information about the "convert" command and the options available, see the ImageMagick convert documentation.