[Interest] Qt 4.7.1 windows printing crash/black results

Paul Miller paul at fxtech.com
Wed Feb 22 17:57:53 CET 2012


On 2/22/2012 10:49 AM, Bo Thorsen wrote:
> Den 22-02-2012 17:38, Paul Miller skrev:
>> On 2/22/2012 10:25 AM, Paul Miller wrote:
>>> On 2/22/2012 10:08 AM, Paul Miller wrote:
>>>> My next step is to build a test program that hopefully shows the
>>>> problem
>>>> but I'm hoping someone might know what's going on. I must reiterate the
>>>> code used to work with older versions of Qt.
>>>
>>> I whipped up a simple test program and it works fine. As far as I know
>>> the printing code in in my application is roughly equivalent, so I
>>> really don't know what is going wrong here.
>>
>> FOUND IT!
>>
>> I was drawing QImages with Format_RGB32 and I suppose somewhere down in
>> the driver it was treating it as a 3-channel image (which it didn't do
>> in 4.5). I switched my QImage to be ARGB32 and it works fine now.
>
> Sounds like a bug. Will you put this in the bug tracker?

Agreed. Yes, I'll file a bug and modify my test program to show the problem.

I had been using the RGB32 format because although my buffer has 4 
channels, I wanted the alpha to be ignored entirely. Though technically 
at least for printing ARGB32 format is a decent equivalent.



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