Alpha-Blended PNGs?

[kubernetic]

Just out of curiosity, why are alpha blended PNGs not supported in GameEx Themes?

This seems to me to be the whole point of using PNG images. If you don't plan on allowing them to be alpha-blended, just use GIF files instead, as they are able to be parsed and rendered more quickly, and would take less memory to display.

It just seems to me that supporting PNG alpha-blending would be natural, since you already have it for the fonts and videos, and it doesnt seem like it would be that much harder to implement.

Just my thoughts anyways. I would appreciate anyone else's insight!

--------EDIT------------

Where are my manners?

In my haste to share my opinion, I totally forgot to mention what an excellent program this is. Many thanks and apologies for Tom, and all else involved. I feel so bad that it took WTB's post to remind me. I feel all humbled an n00bish...

Now if you'll excuse me, i'm going to jam my hand in a wood-chipper for such an oversight!

[WTB]

I was just thinking the same thing. It would open up a lot of options for custom skinning this app. Great work, by the way, Tom. I haven't had this much fun in a long time.

-Matt

[Tom Speirs]

Just out of curiosity, why are alpha blended PNGs not supported in GameEx Themes?

This seems to me to be the whole point of using PNG images. If you don't plan on allowing them to be alpha-blended, just use GIF files instead, as they are able to be parsed and rendered more quickly, and would take less memory to display.

It just seems to me that supporting PNG alpha-blending would be natural, since you already have it for the fonts and videos, and it doesnt seem like it would be that much harder to implement.

Just my thoughts anyways. I would appreciate anyone else's insight!

--------EDIT------------

Where are my manners?

In my haste to share my opinion, I totally forgot to mention what an excellent program this is. Many thanks and apologies for Tom, and all else involved. I feel so bad that it took WTB's post to remind me. I feel all humbled an n00bish...

Now if you'll excuse me, i'm going to jam my hand in a wood-chipper for such an oversight!

Hi,

Do you mean supporting the Alpha Colour/Channel in PNGS, or actually alpha blending, meaning opacity? Alpha Blending is just not possible in GameEx as it uses DirectDraw and not Direct3D.

Using an Alpha Colour from a PNG is possible, I think it does already do this for logos but translates the Alpha Channel to black. Could please clarify exactly what you are asking for?

Thanks.

[djrobx]

They're referring to the alpha/opacity channel. It certainly is possible to implement the png alpha "blending" with the surface it's being drawn on in DirectDraw, although I did it "manually" by including libpng in my project. You implement a function to get the current surface bits and it will perform the alpha blend for you.

-- Rob

[Tom Speirs]

They're referring to the alpha/opacity channel.  It certainly is possible to implement the png alpha "blending" with the surface it's being drawn on in DirectDraw, although I did it "manually" by including libpng in my project.  You implement a function to get the current surface bits and it will perform the alpha blend for you.

-- Rob

Are we talking about Alpha blending one direct draw surface onto another or Loading a PNG, then loading that image into a surface and using the Alpha colour as the colourkey? I did not think the former was possible with DirectDraw like rotation is not?

[djrobx]

Are we talking about Alpha blending one direct draw surface onto another or Loading a PNG, then loading that image into a surface and using the Alpha colour as the colourkey? I did not think the former was possible with DirectDraw like rotation is not?

<{POST_SNAPBACK}>

GIFs use a colorkey. PNG supports varying degrees of opacity based on the value of the alpha channel. That allows you to create say, a blurred drop shadow without concern for the color it's going to be used ontop of.

It's hard for me to talk intelligently about how it would be applied to the way you're using it in DirectDraw since I have not seen your code.

[Tom Speirs]

OK Let me answer the original post now I understand what was being asked.

Why dont themes support alpha blended PNGS, but Videos and Text does.

First of all. Fonts are not alphablended. It might look like they are at higher resolutions, but believe me that took some tweaking with the colours.

Videos are alphablended yes, but this is done without using your video hardware but in software. This is very slow. Anything below a Radeon 9200 and 2Ghz and your pc will grind to a crawl if not already.

GameEx uses DirectDraw which does not support Alpha Blending or Rotation using Hardware acceleration (on 99% of video cards). Alpha Blending is possible in GameEx, but needs to be done in software and not using DirectX which is again extremely slow, so thats why its not done.

Thanks.