AutoHotkey Community

[Drugwash]

I tried out Bobo's code out of curiosity. With Size := 0.8 it created a 599kB PNG 1638x614. With Size := 1 it created a 187kB PNG of the same screen (fullscreen 2048x768 - dual monitor).
Why would a smaller image be that much larger after resize? It's also very slow (a few seconds on 700MHz CPU), compared to ScreenGrab also set to save PNG.

Tested in Win98SE.
_________________

[tic]

Heh that stumped me for a bit, but I think I have figured out why. It's a bit weird though Because of how a pngs compression works, the smaller resolution file is actually larger in filesize as it has more colours because when an image with a single black pixel on a white background is shrunk, then it becomes a black pixel with some shades of grey pixels round it on a white background. This makes sense to me but may not be the case (im just trying to explain it) as I have looked through the code and can see no reason why this would happen. They are both the same colour depth. When testing with an image format with no compression (bmp) you can clearly see the larger reolution is a proportionally larger filesize.

There are a number of reasons for potential slowness. As Bobo has put the whole image resizing and saving into a function then the bitmap needs to be created twice in memory every time, when only once is needed, and there should also be a check to make it so that it doesnt resize it if the size is set to 1. You probably already saw nut it also uploads it to the internet which cant be counted in the time taken. On a test on my comp it took 125ms to completely save the file to disk and I can see that actually writing to disk takes the largest chunk of time (all the rest takes around 40ms) so the disk is what is slowing it down. I actually think Bobo's script is quite nice now that I've tested it but it could be optimized a tad

ps. The image at 1 had 3531 unique colours and the smaller 0.8 one had 5598

[Drugwash]

Hi, thanks for replying.

I just checked and the 0.8 image has 34578 colors, while the 1 image has 5226, both at 32bpp. Quite a discrepancy, I'd say...

As for the time taken, I should've mentioned I used the previous code, not the function one that also uploads it.

It seems to be the resizing that takes all that time and possibly the fact that the CPU is already ~70% busy. I added a check to skip resizing if size is 1 and it now saves it much faster, complete with timestamp watermarking.

All in all it's a nice and useful script and I may improve it a bit - if I manage to understand all of the tricks - especially in the timestamp area, which could use a semi-transparent background. But for now it's just an idea.

Oh and I forgot to say: too bad your tutorial examples don't work in Win9x... Would've been really useful for me to learn all GDI+ functions. Maybe you could consider some non-layered examples, time allowing.
_________________

[tinku99]

Is there a way to convert a pgm image into a bitmap with gdiplus.ahk without having to loop with the setpixel function?
basically how do you get from a 2 dimensional array of 32bit integers (argb pixels) to a bitmap ?
I want to do something like this using just ahk:
http://www.codeguru.com/cpp/g-m/gdi/gdi/article.php/c3705
Thanks.

[tic]

DrugWash:

might have fewer colours with a different interpolation mode:

[tinku99]

I am doing some image manipulation: edge detection, segmentation. I need to be able to display binary images as well as gray scale images with different ranges for the pixel values. My images are in dicom, but i convert them to a 2d matrix for the image manipulation.

I am working with an ecl(lisp) dll under ahk.
works a lot like the ws4ahk.ahk for lisp.
i could write out my data to a file, convert to jpg and then use gdiplus, but thought i might skip the disk writing step.

Here is something close to what i want:

http://www.autohotkey.com/forum/viewtopic.php?t=14941&highlight=include+images

instead of this function:
CreateBitmapInMemory(_imageHexData, _guiID)
i want a similar curried function that takes a 2x2 array, and maybe three other arguments such as width, height, and pixel depth.tuch as width and height and pixel depth

[tinku99]

http://www.autohotkey.com/forum/topic32225.html&highlight=bitmap

Figured it out... used your function in the link above combined with the above...
is kind of dirty, will try to clean it up later.

requires gdip.ahk and filehelper.ahk

[Drugwash]

[tic]

tinku99:

You'll see that I already had those functions, but for a different purpose in Gdip_BitmapFromBRA() which I have as of yet not told anyone how to use
You do not need to numput all the header info into a bitmap to create a blank bitmap, just use Gdip_CreateBitmap()

Drugwash:

When I was referring to

[Drugwash]

Ah, I see. However, seeing that even level 7 kinda breaks the image, I couldn't imagine what level 2 or 1 would do to it.

I'll be around, waiting for that super-duper progressbar. Good luck with it!

P.S. My Win98SE system is skinned with Tihiy's Uberskin and it takes over the regular progressbar's color. I'm curious if you can work around this.
_________________

[tic]

Example 9 uploaded. A quick demonstration to create new controls on a gui using the library (In this case a custom progress bar)

[Drugwash]

Thanks, it works... almost.

The progress bar is correctly drawn - from what I can tell - but it appears at random times, after clicking and/or dragging the slider to various positions and it doesn't follow the correct position (percentage) of the slider.

Then when the window is sent to back and back to front (focus a bigger window that covers it and then refocus the example, the progress bar is simply not there; will appear after more clicking/dragging around.

Otherwise it's a neat example and I may consider using this technique with the toy I'm working on.

Thanks again and have a great week ahead!
_________________

[ewerybody]

Hey tic!
awesome work! Intense man!!

I was just trying to do some image editing stuff but I need rotate and scale.
No examples yet? I'm crapping up getting it to work? reset what??

And hey Drugwash: lol! I know you frum miranda-forum. Thats how nerds meet ^^

[ewerybody]

still no success.
According to the header:
Gdip_RotateWorldTransform and Gdip_ScaleWorldTransform return
; InvalidParameter = 2

I don't know how the given picture or an angle value of maybe 90 can be invalid? Is the bitmap the wrong point to start? can I only rotate graphics (G)?

Someone else had success with rotating and scaling?

And can I flip an image via negative scale?

[tic]