Native or third?
lazarus / 39-Graphics

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fabiopesaju · 2017-05-12 16:44

I need to read multiple images, and display them in full screen, one
by one ... which is the best and fastest component recommended for
this? Are many images and are large, high resolution. The ideal would
be to preload them before the show, correct?

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Thaddy · 2017-05-12 16:48

Unless you have loads of memory:no. But you can cache a couple or so
in memory and side-load the same TImage control with a new picture
after show.

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fabiopesaju · 2017-05-12 16:58

thank you...

and what do you recommend? use native components for image?

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Ñuño_Martínez · 2017-05-15 07:20

If you're doing just displaying the image, TImage should be enough. 
If you're doing more complex stuff then it depends on what you want to
do.

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fabiopesaju · 2017-05-15 12:16

Are several steps ... of a very simple project ...

At first, I want to make a kind of image presenter, like a powerpoint,
but just displaying images.

Then I want to apply some simple transition effect, such as zoom in,
zoom out, from some predefined point in the image... next to some spin
effect...


I continue with Timage, or is there any other component better?

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Handoko · 2017-05-15 12:40

TImage is good for showing image only. But if you want to do
animations or effects, it is not suitable. You should use other
library, maybe you can try BGRABitmap, it has easy to follow
tutorials:

http://wiki.lazarus.freepascal.org/BGRABitmap_tutorial

Here a list of other available libraries you may want to know:

http://wiki.freepascal.org/Graphics_libraries

But if performance is your top priority you should use OpenGL or
DirectX (for Windows only). Learning OpenGL is harder than others, but
maybe you want to give it a try:

http://wiki.lazarus.freepascal.org/OpenGL_Tutorial
http://wiki.lazarus.freepascal.org/OpenGL

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franciscoluiz · 2017-05-17 12:29

thanks, I'm with him... and we'll take a look at opengl...

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Handoko · 2017-05-17 12:52

To enable opengl on Lazarus:
Lazarus main menu > Package > Install/Uninstall Packages > on the
right panel, choose: "lazopengl context 0.0.1" > click: "Install
Selection" > Save and Rebuild IDE > wait several minutes and restart
your Lazarus IDE.

If you're using Linux, you need to install libgl1-mesa-dev.

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marcov · 2017-05-17 12:56

My opengl image display widget is in this thread .

It also allows to draw simple forms on top of the image, and has a
small range of zoom options.

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Handoko · 2017-05-17 13:37

Downloaded and tested but the result isn't good. 

I can run the attached executable on Linux using Wine. It worked but I
noticed something weird. After several configuring and clicking, it
crashed.

Tried to open the source to run using my Lazarus, but it failed to
compile because it depends on Windows unit.

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marcov · 2017-05-17 13:39

It is a Windows application, and never was used on Linux. I don't know
if Wine is sufficient compatible. (though afaik only a few opengl
calls are windows specific mostly context creation)

There are no principal reasons why it couldn't run on non windows
except time and motivation.

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Handoko · 2017-05-17 13:53

I ever followed your signed distance font concept, it's really a great
idea. Hope someday you can finished it and make it cross-platformed.