Partial transparency appears as wrong color

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bitoboy
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Joined: Tue Aug 07, 2007 6:25 pm

Partial transparency appears as wrong color

Post by bitoboy » Thu Aug 09, 2007 7:07 pm

Please assist!

I just purchased a site license of the gdviewer product. I am loading a PNG file with partially transparent pixels onto a background that changes.

However, the partially transparent pixels are showing up as though they were being mixed with blue instead of the background image.

Here's the original PNG.

ftp://ftp1.respironics.com/downloads/mi ... PNG24b.png

Here's what it looks like on my form.

ftp://ftp1.respironics.com/downloads/mi ... roblem.bmp

Thanks for your assistance!

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Loïc
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Post by Loïc » Fri Aug 10, 2007 4:59 pm

Hi,

You can bypass this behaviour using the last 2.8.3 edition and setting the backcolor value of the GdViewer control as the same as Your form.

ex:
If the backgroud color of your form is RED RGB(255,0,0)
Set the backgroud propertie of the gdviewer to RED too...


Best regards,

Loïc

bitoboy
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Joined: Tue Aug 07, 2007 6:25 pm

Post by bitoboy » Fri Aug 10, 2007 5:54 pm

Loic,

2.8.3 fixed it. Thanks!

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Loïc
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Post by Loïc » Sat Aug 11, 2007 10:29 am

You're welcome!

Thanks for the return.

Best regards,

Loïc

bitoboy
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Joined: Tue Aug 07, 2007 6:25 pm

Post by bitoboy » Thu Aug 16, 2007 6:30 pm

Loic,

I goofed. At further inspection, it's clear that the color that the partially transparent pixels are getting mixed with is black. I thought it was just the PNG file, but we lightened those pixels and they still show as black.

It's as though partial transparency is ignored entirely.

What am I doing wrong?

Please keep in mind that I am using a gradient fill background. So there is no single background color. In any case, I set the background color of the object to a color that was close to the gradient fill and it still shows black.

Argh. Please help.

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Loïc
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Post by Loïc » Tue Aug 21, 2007 10:42 am

Hi,

The control allows only one color as full transparency. The others like you said are mixed with the background of the control.

The GdViewer [pro] 2.8.4 gets few improvements to displays this kind of image.

However, the best way to displays 32 bits image with alpha chanel is to use the Display functions of the GdPicture Pro components.


Best regards,

Loïc

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