[reportlab-users] How to save drawings with transparent background as PNG?

[Dinu Gherman]

Hi,

a few months back I asked the question below, which, sadly, hasn't attrac-
ted any feedback, yet. I'm still interested to know if there is a way to 
do this inside reportlab or if I absolutely have to use pure PIL for over-
laying existing bitmap images (not exactly what the code below does).

Regards,

Dinu


On March, 11th, 2012 I wrote:


> Hi, 

> 

> it seems like I am trying to do an impossible thing: generate a drawing 

> and save it as PNG with transparent background, see code below. Reading

> the source code for renderPM provided little insight, so I wonder if it

> can be done and how? (I'm using RL 2.5, BTW.)

> 

> Thanks,

> 

> Dinu

> 

> PS:

> 

> from reportlab.lib import colors

> from reportlab.graphics.shapes import Drawing, String

> from reportlab.graphics import renderPM

> 

> d = Drawing(100, 100)

> s = String(50, 50, "foo bar", 

>        fontName="Helvetica", fontSize=18, 

>        textAnchor="middle", 

>        fillColor=colors.black)

> d.add(s)

> 

> renderPM.drawToFile(d, "test.png", fmt="PNG", bg=None)

> p = renderPM.drawToPIL(d, bg=0xffffff, configPIL={'transparent': 0xffffff})

> p.save("test-pil.png")