Show picture+Make it disapear after a Delay

[WharfRat]

Hi guys,

I am not having any success with the alpha channel of a PNG using this script.

Enclosed is the PNG file in a ZIP, because it seems that the forum strips the alpha channel.

alpha.zip

alpha.png

(38.39 KiB) Downloaded 198 times

The alpha.png file in the ZIP has an alpha channel which is a horizontal gradient.

The file is correct, because I tested it on a web page with a background image:

test.png (140.2 KiB) Viewed 6503 times

However, this is the result I get with this script when showing the file on the desktop:

result.png (60.91 KiB) Viewed 6503 times

All I get is the transparency showing some kind of grey background instead.

Am I doing something wrong, or is there some limitation of wxPython that I am not aware of. Right now I have no experience with wxPython. I need to finish learning Python first.

Eventually I want to implement a semitransparent screen overlay with text and graphics. Without semitransparency, the idea is dead in the water. It would be great if it could become some sort of GDI plugin, if you see what I mean.

Anyway, thanks for your time...

[Pako]

You're right, I can confirm.
Both actions (System.ShowPicture and System.DisplayImage) displays the file incorrectly.
I tried a simple thing. I used it as an "icon" in PushBullet plugin (action Push mirror) and it looked like this:

AlphaTestMirror.png (8.13 KiB) Viewed 6486 times

This means properly.
And since I'm the author PushBullet plugin and also the action System.DisplayImage, so it should not be a big problem to fix it.

Pako

[WharfRat]

Aah, thanks Pako

I was thinking that I would have to learn ctypes to program GDI and DCs directly...

I will take a look at PushBullet sometime since I am not familiar with it.

Thanks for everything that you do...
You can have one of the roses in my hand over there while I go out to buy you a beer.

[WharfRat]

Okay, so I should be looking at PIL then... thanks for pointing me in the right direction.
I'll have to get the docs for that too.

[Pako]

I'm a bit improved behavior of Display Image action.
Now is better taken into account the value of the alpha channel:

alpha.png on a yellow background

alpha_yellow.jpg (23.25 KiB) Viewed 6465 times

However, I do not think it will be sometime in the future so perfect that will be rendered semi-transparent image on a transparent background.
I'm not saying it's impossible. But it is at least very difficult, and I have no interest in spending more time on it.
Modified System plugin can be downloaded here.

Pako

[WharfRat]

Thanks Pako, I'll take a look at it

[WharfRat]

Thanks for your effort Pako, you don't need to spend any more time with this.

I just want to clarify what I said earlier.

The result.png image obtained previously did not use System.ShowPicture or System.DisplayImage, but used the script that you posted here for themaster1 in 2011.

System.ShowPicture ignores all transparency and alpha values:

ShowPicture

ShowPicture.png (27.31 KiB) Viewed 6443 times

The original System.DisplayImage:

old DisplayImage

DisplayImage_old.png (63.47 KiB) Viewed 6443 times

The new System.DisplayImage:

new DisplayImage

DisplayImage_new.png (85.73 KiB) Viewed 6443 times

In the old and new System.DisplayImage cases, alpha < 127 is opaque, and alpha > 127 is transparent.
There is a slight visible difference between the two versions, but I don't think the modification is worth releasing.

The script from the 2011 post was more effective, it resulted in displaying the whole image.

An interesting observation about the script: you can only drag and click the non-transparent regions... Cool! I can already envision OnScreen Sliders and other GUI controls.
Try the script with this image:
(see the next post)

Anyway, back to the alpha channel. I will start with the script implementation and see if I can do anything with that. A look at the WxPython website is probably a good idea, but it looks like it might have to be GDI and DCs. If I get anywhere, then this will continue in the Coding forum, with a note about that here.

[WharfRat]

Here is the other image for the previous post:

transparent.zip

transparent.gif

(1.38 KiB) Downloaded 179 times

(I just found out that each post can only have 3 attachments)

[Pako]

In the old and new System.DisplayImage cases, alpha < 127 is opaque, and alpha > 127 is transparent.

Yes this is the default behavior.
It would be possible to add the option to choose the threshold (from 0 to 255).

There is a slight visible difference between the two versions, but I don't think the modification is worth releasing.

I think that you are not right.
The difference is especially noticeable when the Shaped window (if alpha channel exists) option is unchecked.

Note: The difference between the old and the new version is more:

• Background color behavior
• Doubleclick behavior [when Shaped window (if alpha channel exists) option is unchecked]

Pako

[WharfRat]

I must apologize for not testing the modification more thoroughly. Yes, System.DisplayImage does work better now:

Shaped window unchecked

Shaped_window_unchecked.png (55.19 KiB) Viewed 6415 times

I was also not aware of the double-click feature. So sorry...

[WharfRat]

Something just occurred to me...

All this time I have been wanting a partially transparent image.
Maybe I should use a chessboard pattern in the alpha channel instead.
I think the technique is called 'half-toning' or something like that.
Better get back to GIMP.

This seems to be the easiest solution, I'll try it now.

[Pako]

I was also not aware of the double-click feature. So sorry...

You do not have to apologize.
I think that almost nobody knows.
I did no promotion for it: New action System\Display Image
But I've long ago given up. Usually when I do something new, most people have no interest in it.
So why would I bother (write English is difficult for me).

Pako

[WharfRat]

DisplayImage result with chessboard alpha

result_chessboard.png (184.99 KiB) Viewed 6398 times

Here is the PNG file in the archive:

alpha_chessboard.zip

alpha_chessboard.png

(31.63 KiB) Downloaded 167 times

So, it works.
Sadly, on my system, the DisplayImage action takes about 10 seconds to process before the image is displayed. I can only guess that it has to calculate the shaped window thing.
Let me also say that this was using the original System.DisplayImage and not the newer one, although I will test it with that one later.

By the way, I am always very interested in what you do.
No one can afford to miss a thing.
I understand everything you have written perfectly.
Even your humour comes through clearly (uncle Google, the problem is on the other side of the screen, etc.), I still laugh at those two.