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Author Topic: Gdi+ image operation  (Read 12392 times)

Offline John Z

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Re: Gdi+ image operation
« Reply #15 on: February 24, 2023, 03:34:18 PM »
Hi bitcoin,

Well I'm taking a stab in the dark at it.....

Isn't the png format always a lossless compression?  In lossless compression the quality value
would be meaningless so the compression would always be the same....

jpg is not necessarily lossless so the quality value less than 100 has an effect on the compression
and therefore the size.

John Z

Offline bitcoin

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Re: Gdi+ image operation
« Reply #16 on: February 24, 2023, 04:30:23 PM »
Isn't the png format always a lossless compression?  In lossless compression the quality value
would be meaningless so the compression would always be the same....
May be, you are right..

Offline frankie

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Re: Gdi+ image operation
« Reply #17 on: February 25, 2023, 10:45:42 PM »
As John said the PNG format is lossless, what could be changed is the compression level (see this).
You may want use the "EncoderCompression" GUID instead of "EncoderQuality".
I made same experiments, PNG encoder only accepts a custom parameter block that is undocumented. I made many searches in the net, but no info seems to be available.
« Last Edit: February 26, 2023, 05:13:06 PM by frankie »
It is better to be hated for what you are than to be loved for what you are not. - Andre Gide

Offline Robert

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Re: Gdi+ image operation
« Reply #18 on: March 02, 2023, 04:33:35 AM »
Hey frankie:

All this talk about GDI+ reminded me that I noticed a recent update to your FSDK.

https://github.com/Frankie-PellesC/fSDK

I must have missed the announcement but anyway Thank You for the FSDK GDI+ User Manual.

A monumental piece of work. Truly a tour de force.

Offline frankie

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Re: Gdi+ image operation
« Reply #19 on: March 02, 2023, 10:12:31 AM »
Hello Robert
Thanks
You're right There was no announcement. The manual has been realized many years ago, 2016, together with the 'fGdiPlusFlat.h' and posted on the forum (here).
Few days ago looking at my github pages I realized that the manual was missing and simply, and silently, added it.  :)
My SDK is getting old and would need some mainteinance and upgrade, but unfortunately I'm too busy to afford the job up to now  :(
I hope I could do it in the future.  :P
It is better to be hated for what you are than to be loved for what you are not. - Andre Gide