[reportlab-users] Transparent PNG support

[Paul McNett]

Tim Roberts wrote:


> Darryl Woods wrote:

>> Hi all,

>>

>> I am creating a report with ReportLab, and as part of this I have

>> extended the Table class to do some custom drawing for table borders

>> and such.  Part of the design, however, is that the right side of the

>> tables "fade out" to white, using a gradient. (The report was designed

>> by a graphic designer...)

>>

>> I've tried various things:

>>

>> - placing a dithered black/white GIF image and setting the

>> transparency mask (looks very bad)

>> - placing a PNG with transparency (transparency doesn't appear)

>> - drawing a series of vertical lines, getting increasingly lighter (no

>> transparency though)

>>

>> Is there any way I can accomplish this?

> 

> How good does it need to be?  In my view, your last option is the best one:

> 

> from reportlab.pdfgen import canvas

> from reportlab.lib.pagesizes import LETTER

> inch = 72

> 

> canv = canvas.Canvas( 'try.pdf', pagesize=LETTER )

> canv.setPageCompression( 0 )

> 

> # Rectangle from 72,72 to 360,360 in 20 steps.

> 

> for i in range(20):

>     d = i

>     canv.setStrokeGray( i/20.0 )

>     canv.rect( 72+d, 36+d, 360-d-d, 360-d-d )

>     canv.setStrokeGray( 1.0-i/20.0 )

>     canv.rect( 72+d, 396+d, 360-d-d, 360-d-d )

> 

> canv.showPage()

> canv.save()

> 

> This is drawing in units of 1 pixel.  You could reduce the stroke width

> to 0.5 and do twice as many steps.



Points, not pixels, right?


Paul

-- 
http://paulmcnett.com