Wand alpha() function in Python (original) (raw)

Last Updated : 25 Apr, 2025

The alpha() function is identical to the wand color() function. Similar to color() function, alpha() function draws a color on the image using current fill color, starting at specified position & method. Uses same arguments as color() method.

Syntax: wand.drawing.alpha(x, y, method) Parameters :

Parameter	Input Type	Description
x	numbers.Integer	start of filling color
y	numbers.Integer	end of filling color
method	basestring	method from PAINT_METHOD_TYPES

The following are the PAINT_METHOD_TYPES:

• ‘point’ alters a single pixel.
• ‘replace’ swaps on color for another. Threshold is influenced by fuzz.
• ‘floodfill’ fills area of a color influenced by fuzz.
• ‘filltoborder’ fills area of a color until border defined by border_color.
• ‘reset’ replaces the whole image to a single color.

Note: This method replaces matte() in ImageMagick version 7. An AttributeError will be raised if attempting to call on a library without DrawAlpha support. Example #1:

Python3

from wand.image import Image

from wand.drawing import Drawing

from wand.color import Color

with Drawing() as draw:

`` draw.alpha( 100 , 100 , 'point' )

`` with Image(width = 200 ,

`` height = 200 ) as img:

`` draw.draw(img)

`` img.save(filename = 'color.png' )

Output: A pixel is visible at center of transparent image here is the zoomed image. Example #2: Filling color using a flood-fill algorithm.

Python3

from wand.image import Image

from wand.drawing import Drawing

from wand.color import Color

with Drawing() as draw:

`` draw.fill_color = Color( 'blue' )

`` draw.alpha( 10 , 35 , 'floodfill' )

`` with Image(width = 200 ,

`` height = 200 ,

`` background = Color( 'white' )) as img:

`` draw.draw(img)

`` img.save(filename = 'color2.png' )

Output: