image - How to output transparent PNG with Pycairo? -

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image - How to output transparent PNG with Pycairo? -

here's code:

import cairo import os pil import image imagesize = (512,128) surface = cairo.imagesurface(cairo.format_argb32, *imagesize) cr = cairo.context(surface) cr.select_font_face("verdana", cairo.font_slant_normal, cairo.font_weight_normal) cr.set_font_size(24) cr.set_source_rgb(1, 1, 1) ... surface.write_to_png("myimage.png")

as can see i'm drawing white text png, background defaults opaque black. how create png transparent white text showing?

i able setup transparent background using set_source_rgba() , using 0.0 alpha value:

cr.set_source_rgba(0.0, 0.0, 0.0, 0.0) # transparent black cr.rectangle(0, 0, 512, 128) cr.fill()

had create sure write text this:

# set writing color white cr.set_source_rgb(1, 1, 1) # write text cr.move_to(100,50) cr.show_text("hello") # commit surface cr.stroke()

here's total code works me:

import os pil import image imagesize = (512,128) surface = cairo.imagesurface(cairo.format_argb32, *imagesize) cr = cairo.context(surface) # paint background cr.set_source_rgba(0.0, 0.0, 0.0, 0.0) # transparent black cr.rectangle(0, 0, 512, 128) cr.fill() # setup font cr.select_font_face("verdana", cairo.font_slant_normal, cairo.font_weight_norma cr.set_font_size(24) cr.set_source_rgb(1, 1, 1) # write font cr.move_to(100,50) cr.show_text("hello") # commit surface cr.stroke() # save file surface.write_to_png("myimage.png")

image transparency python-imaging-library pycairo

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