Fast loading of images
lazarus / 39-Graphics

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phoenix27 · 2023-04-12 05:23

I made a program with electron which basically loads full images(50
per page but the number can be changed), then resizes them on the fly
to fill the div container and shows them. It's pretty fast. Now i
decided to make the same program with Lazarus and free pascal because
i like wirthian languages, so different from the others, also compiled
apps feel more personal and also because i always tend to go against
the crowd. The problem is that it's too slow when loading and resizing
the images. Why is a compiled program slower than javascript!! Anyway
the code i use to load the images is basically this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
loadImages(images: ImageCollection);var   bmpDst: TBitmap;   rsrc,
rdst: TRect;   img: imageRecord;    i: integer;begin  for i=0 to
length(images) - 1 do  begin     img:= images[i];     pic :=
TPicture.create;     pic.LoadFromFile(img.thumbAbsPath);     //for
resizing      bmpDst := TBitmap.Create;      bmpDst.Width :=
img.width;//width and height are the resized dimensions of the image,
calculated in advance      bmpDst.Height:= img.height;      rdst:=
Rect(0, 0, bmpDst.width, bmpDst.height);      rsrc := Rect(0, 0,
pic.bitmap.Width, pic.bitmap.Height);     
bmpDst.canvas.CopyRect(rdst, pic.bitmap.canvas, rsrc);      pic.free; 
end   paintBox.invalidate();end;//then in the paintBox  OnPaint event
handler i draw all the saved bmpDst  bmpDst.Draw(paintBox.Canvas,
Bounds(img.left, img.top, img.width, img.height)); If the images are
large in size it becomes even slower. What can i do to improve the
performance? Is there a library which is fast for these things? Or
there is something already there that i dont know about? I started
programming in pascal just some weeks ago so i'm not an expert by any
stretch of imagination . The thing that bothers me the most is that
electron and javascript are fast and pascal, a compiled language is
not  I don't want to resize the images and save them on the disc. I
want to do it on the fly and with an acceptable speed. Some Pascal
expert can tell me how?

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domasz · 2023-04-12 07:58

In your Electron app you use BMP, PNG or JPEG?
PNG and JPEG are smaller. While they need more CPU power to decode
than BMP images they can be loaded from HDD/SSD a lot quicker. IF you
use PNG/JPEG in Electron then use the same format in Lazarus.

Your Electron app used multi threading and your app doesn't. If your
processor has 8 cores than Electron can decode images 8 times quicker.
You should use threads in your Lazarus app.

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balazsszekely · 2023-04-12 08:08

QuoteThe thing that bothers me the most is that electron and
javascript are fast and pascal, a compiled language is notIt's not
about the language, electron and javascript gets a lot of attention
lately, pascal not so much. Probably somebody wrote a fast image
processing library for javascript. With that said, your pascal code is
far from optimal. You recreate Pic on each iteration, you only use a
single thread, more over Bimtap.Canvas operations are notoriously
slow. You should switch to BGRABitmap or other component.

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phoenix27 · 2023-04-12 08:53

@domasz They are exactly the same images, all JPEG.  Only in electron
they show up almost instantly while in Pascal i have to wait about 10
seconds to see those 50 images. I feel like javascript is just  the
scripting language of the real deal, chrome engine, just like i dont
know, Lua is the scripting language of a c++ game. Thats why i dont
like web programming so much. I want MY app. Not an app that runs
within a bigger app( although an Operating System could be seen as a
bigger app too, but thats a bit different). Before electron i made the
same app as a web server in nodejs( which is again google v8 engine)
and firefox as  the client and the same pictures showed up fast.
@GetMem Yes i tried BGRABitmap  like this
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i pic :=
TBGRABitmap.Create(img.thumbAbsPath);//to resize i didBGRAReplace(pic,
pic.Resample(img.width, img.height, rmSimpleStretch)); But that too is
slow.  I tried also to just load the visible part of the canvas, and
thats better; then i put a timer to load the rest and it  slowed
things down again because  after all the loading happens in the same
thread. I tried to use the TWCThread component to load the pictures in
another thread. But i dont know how to pass the pictures in the new
thread(it expect a variant type, but i don't think you can pass
whatever value). Also i read that the LCL isn't thread safe so i
cannot use TBitmap and all the other classes. So how am i supposed to
load and resize those images? Threads seem a complicated business and
i'm just an amateur programmer. Some practical solutions would really
be appreciated.

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phoenix27 · 2023-04-12 09:08

My strategy wold be this: I load only the visible part of the canvas
and at the same time i spawn some threads to resize the rest of the
images. But i would like to know, how can i pass an image and the new
size to the new thread and once in there can i use the Tbitmap,
TPicture classes to load and do the resizing and then pass back the
result?
How can i do that? Somebody can post some code?

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wp · 2023-04-12 09:40

If you are mainly interested in thumbnails check out theos thumbnail
viewer; it uses multiple threads for loading.
(https://github.com/theo222/lazarus-thumbviewer).

In case of jpg and thumbnail generation, use the "Scale" property of
TJpegImage (jsHalf, jsQuarter, jsEighth); the loading time decreases
accordingly. There is also a Performance property which, if set to
jpBestSpeed, gets you another about 50% speed gain. See attached demo
(it loads the lazarus cheetah by default which is quite small; use a
larger image to better see the differences).

Use a fast jpeg reading library. I once worked with Intel's IJL
library and found it to be much faster than the standard JPG reader
that comes with FPC (it's no longer supported and Windows only,
though). There are others but I never worked with them.

Create a cache of scaled images that already have been loaded.

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SymbolicFrank · 2023-04-12 10:13

Another thing is, that the pictures are completely processed before
they're displayed, while in the browser you first get a blocky, low-
res image, that becomes sharper the more it is processed.

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marcov · 2023-04-12 10:31

Maybe first time what the bulk of the delay is. E.g. by first loading
50 images and only then drawing them all fifty with copyrect and
finally the stretchdraw and timing all those three stages.

My money is on the stretchdraw, the default Windows canvas (GDI) is
simply not the fastest, which is why I converted to using Opengl in my
image related programs.

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phoenix27 · 2023-04-12 14:43

@wp i had already tried theos thumb viewer, yes its quite fast at
processing but then when i had all the images on the canvas scrolling
up and down was painfully slow
As  for the TJpegImage i tried your code and works well, but  in my
case it always crashes on the line:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i jped :=
TJpegImage.create I dont know why.
I did read a tutorial on multithreading and came out with this
solution.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i Type 
TGiveMediaEvent = procedure(bitmap: TBitmap; idx: integer) of Object; 
TMyThread = class(TThread)  private    FOnGetNewMedia:
TGiveMediaEvent;    mi: MediaInfo;    bmp: TBitmap;    _midx:
integer;    procedure getNewMedia;  protected    procedure Execute;
override;  public  Constructor Create(CreateSuspended : boolean); 
property OnGetNewMedia: TGiveMediaEvent read FOnGetNewMedia write
FOnGetNewMedia;  property media: MediaInfo read mi write mi;  property
Bitmp: TBitmap read bmp write bmp;  property midx: integer read _midx
write _midx;end;constructor TMyThread.Create(CreateSuspended :
boolean); begin   inherited Create(CreateSuspended);   FreeOnTerminate
:= True;   mi:= nil;   bmp := nil; end;  procedure
TMyThread.GetNewMedia;  begin   if Assigned(FOnGetNewMedia) then 
 begin     FOnGetNewMedia(bmp, midx);   end; end;  procedure
TMyThread.Execute; var   pic: TBGRABitmap; begin 
 Synchronize(@GetNewMedia);   while (not Terminated) and (mi <> nil)
do     begin       try       pic :=
TBGRABitmap.Create(mi.thumbAbsPath);       BGRAReplace(pic,
pic.Resample(mi.width, mi.height, rmSimpleStretch));       bmp :=
pic.bitmap;       except          pic :=
TBGRABitmap.Create('imgs/image_error.jpg');          BGRAReplace(pic,
pic.Resample(mi.width, mi.height, rmSimpleStretch));          bmp :=
pic.bitmap;       end;       Synchronize(@GetNewMedia); //stops until
the main thread called the method within syncronize     end; end;  
 #then in the app, n the form private sectionprivate  myThread:
TMyThread;  procedure giveNewMedia(bmp: TBitmap; idx:
integer);public ...# and in the implementation procedure
TfrmMediaStore.giveNewMedia(bmp: TBitmap; idx: integer);  var pb:
MediaCanvas; begin    pb:= getActiveCanvas();    if midx <
length(pb.marr) then    begin       myThread.media:= pb.marr[midx];  
   myThread.midx:= midx;       inc(midx);    end    else     
 myThread.media:= nil;    if bmp <> nil then    begin   
 pb.bitmaps[idx] := bmp;     pb.invalidate;    end;  end;   #and in
another proc procedure loadimages();begin  frmMediaStore.midx:= 0; 
frmMediaStore.myThread := TMyThread.Create(true); 
frmMediaStore.myThread.OnGetNewMedia := @frmMediaStore.GiveNewMedia; 
 frmMediaStore.myThread.Start;end                So the main thread
sends to the new thread the image info(media info with path and new
size) and the index of the array where the bmp will be cached, then
the thread load the image and resizes it and then sends back the
bitmap and the index to the main thread which calls invalidate so the
canvas get drawn. The process repeats until all the images are
consumed. Works well!! I created 2 threads and from 11 seconds it went
down to 4-5 seconds. Thats good. It still needs improvement, but i
already like it.

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wp · 2023-04-12 14:51

Quote from: phoenix27 on April 12, 2023, 04:43:19 pmin my case it
always crashes on the line:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i jped :=
TJpegImage.create I dont know why.
Looks like a typo. Shouldn't it read "jpeg" rather than "jped"? Always
have a look a the compiler messages to get an idea why code does not
compile. If it is not a typo you probably do not have the unit
"graphics" in the "uses" clause.

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hukka · 2023-04-12 14:52

I'm working on an image viewer and some of the most important points
speedwise were:
Use libjpeg-turbo for loading JPEGs. On Windows I use GDI+ for loading
most other supported formats; custom routines for less common
formats.If you know the dimensions you'll be downscaling to in
advance, there's no need to decode the JPEG at full resolution.Use
multithreading for image loading. (I see you had success with this
already.)Use BGRABitmap.Have a memory cache for decoded images.

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phoenix27 · 2023-04-12 14:52

One problem that i see to my little solution is that every time a new
bitmap comes from the new thread i call invalidate and so the paint
box gets drawn again and again, although i just draw the visible
area.  I noticed the cpu goes to 20, 26%. What do you people think,
it's faster to draw on a canvas or to assign the images to a TImage
control?

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phoenix27 · 2023-04-12 14:56

@wp it's not the actual code, i just typed it here.
But every single time it crashes on that line. Anyway i suppose
TJpegImage is just for jpeg images, what if in the future i want to
use png or bmp or webp?

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phoenix27 · 2023-04-12 15:06

@hukka "If you know the dimensions you'll be downscaling to in
advance, there's no need to decode the JPEG at full resolution."
My little program works in this way. I have an algorithm of linear
partitioning(i think its called this way) which creates all the rows
based on the width and height of the container. In each row every
image has the same height but width can be different, according to the
aspect ratio of the image. In shorts it looks like a bunch of bricks.
So when i resize the form and the width changes i have to repeat the
process. So it depends on the width and also the height if i change
it. Am i clear? There isn't one predefined dimension.

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VisualLab · 2023-04-12 15:07

Quote from: GetMem on April 12, 2023, 10:08:21 amQuoteThe thing that
bothers me the most is that electron and javascript are fast and
pascal, a compiled language is notProbably somebody wrote a fast image
processing library for javascript. With that said, your pascal code is
far from optimal.

It seems unlikely to me that the script itself is doing this. Rather,
the JavaScript interpreter uses a browser module (part of machine
code) that is responsible for loading and saving raster images. Most
likely, such a module takes (from the interpreter) paths or addresses
and returns (to the interpreter) references to structures that store
the content of images ready to be displayed. The script passes the
drawing command to the rasterizer, giving it references to graphic
structures and areas where they are to be displayed, and the
rasterizer displays them. Given how much graphics a web page contains,
it's no surprise that these parts of browsers have been heavily
optimized. In the most popular web browsers, graphics and multimedia
of all kinds are processed in modules written in C++ and compiled to
machine code (as machine code in an extractable executable file).
These modules are made available to the interpreter as a JavaScript
API. A good example of such automation is Web Audio. Currently,
JavaScript scripts process data only when there is no such module in
the browser (of course, you can write such a "library" in JavaScript,
but it will not be as efficient as an optimized browser module -
unless someone invents some brilliant algorithm, unknown to anyone yet

The question is: how to find in the jungle of Chrome (or Firefox)
source code the module responsible for loading and displaying raster
graphics?

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wp · 2023-04-12 15:12

Quote from: phoenix27 on April 12, 2023, 04:56:30 pmAnyway i suppose
TJpegImage is just for jpeg images, what if in the future i want to
use png or bmp or webp?
Yes, it's what its name says... If you need a multiformat loader you
should use TPicture. But then you are tied to the registered formats
and their readers, so that you cannot optimize them. Some third-party
libraries register their readers in the LCL and replace the built-in
formats, however. Or you read the first few bytes from each file and
determine the file format from the file header and then select the
appropriate reader class yourself - distinguishing between jpg, png or
bmp is really easy. I don't know much about BGRABitmap, maybe it has a
multiformat reader.

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VisualLab · 2023-04-12 15:13

Quote from: phoenix27 on April 12, 2023, 04:56:30 pmBut every single
time it crashes on that line. Anyway i suppose TJpegImage is just for
jpeg images, what if in the future i want to use png or bmp or webp?

PNG -> class TPortableNetworkGraphic
BMP -> class TBGRABitmap

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phoenix27 · 2023-04-12 15:14

@hukka is it fast GDI+ ?. I'm on windows 7, so i could try. How would
i load images with GDI+?

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phoenix27 · 2023-04-12 15:25

@Visual Lab i agree perfectly with you. That's why i said in a
previous post that javascript it's just a scripting language which
allows you to interact with the browser platform just like lua allows
you to simply script a game. But lua is not c++,  in which the game
was created.

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phoenix27 · 2023-04-12 15:41

@wp i noticed that TPicture,  when the extension of the file its
different from the actual format,  raises a 'wrong format' error,
whereas TBGRABitmap doesn't

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wp · 2023-04-12 15:57

Quote from: phoenix27 on April 12, 2023, 05:41:39 pm@wp i noticed that
TPicture,  when the extension of the file its different from the
actual format,  raises a 'wrong format' error, whereas TBGRABitmap
doesn't
Yes it would be fine if there were an option to bypass the exception
in such a case. But you always can load the file into the TPicture via
a stream so that the extension is unknown:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button1Click(Sender: TObject);var  stream: TStream;begin 
stream := TFileStream.Create('test.bmp', fmOpenRead);  // 'test.bmp'
is a 'png' image renamed to 'bmp'.  try    stream.Position := 0;   
Image1.Picture.LoadFromStream(stream);  finally    stream.Free; 
end;end;

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hukka · 2023-04-12 16:01

Quote from: phoenix27 on April 12, 2023, 05:14:52 pm@hukka is it fast
GDI+ ?. I'm on windows 7, so i could try. How would i load images with
GDI+?

Snippet from my image viewer:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
Windows, GdiPlus, ActiveX; function GDILoadImage(Stream: TStream):
TBGRABitmap;var        StreamAdapter: IStream;        BitmapData:
TGPBitmapData;        rec: TGPRect;        gdipBitmap: GpBitmap;     
 Y: Integer;        PP: Pointer;begin        Result := nil;       
try                StreamAdapter := TStreamAdapter.Create(Stream);   
           try                        gdipBitmap := nil;             
         if GdipCreateBitmapFromStream(StreamAdapter, gdipBitmap) <>
Ok then Exit;                        rec.X := 0; rec.Y := 0;         
             GdipGetImageWidth(gdipBitmap, UINT(rec.Width));         
             GdipGetImageHeight(gdipBitmap, UINT(rec.Height));       
               if GdipBitmapLockBits(gdipBitmap, @rec,               
               [ImageLockModeRead], PixelFormat32bppARGB, BitmapData)
= Ok then                        begin                               
with BitmapData do                                begin              
                        Result := TBGRABitmap.Create(Width, Height); 
                                     PP := Scan0;                    
                  for Y := 0 to Height-1 do                          
            begin                                               
Move(PP^, Result.ScanLine[Y]^, Width*4);                             
                 Inc(PP, Stride);                                    
  end;                                end;                           
   GdipBitmapUnlockBits(gdipBitmap, BitmapData);                     
 end;                        GdipDisposeImage(gdipBitmap);           
   finally                        StreamAdapter := nil;              
end;        except                FreeAndNil(Result);       
end;end; function GDILoadImage(const Filename: String):
TBGRABitmap;var        S: TFileStream;begin        Result := nil;    
  if not FileExists(Filename) then Exit;         S :=
TFileStream.Create(Filename, fmOpenRead);        try               
Result := GDILoadImage(S);        finally                S.Free;     
 end;end;

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phoenix27 · 2023-04-13 00:54

Thank you hukka, ill try the code.
I can say i' m satisfied. I put 3 threads at work and now it works
like a charm, it loads all the images in less than 3 seconds. It's
perfect for me. About my app in electron, i have forgotten a couple of
things(i coded it a while ago). First of all i load only the images in
the visible area and i load the rest incrementally while scrolling
down. But more importantly, javascript has only one thread, so you
cannot use multi-threading, but it has a cool feature called the
event-loop(i think it's called like that), which means that I/O
operations(like the loading of images, net or database connections and
so on) happen by default not in the main thread(like it is for free
pascal and most languages and that's why you need multi threading) but
somewhere else and when the process ends you get notified through the
use of callbacks. So we could say that javascript is non-blocking or
async by nature. That's why it looks so smooth. Now i remember that
when i loaded all the images at once there was a noticeable delay,
although it is non-blocking!! That's why i decided to load only the
images in the visible part of the app!

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balazsszekely · 2023-04-13 05:53

@VisualLab
Fair enough. I'm not familiar with the loading mechanism. My point is
javascript gets a lot of love and attention pascal not so much.

@phoenix27
Quote I put 3 threads at work and now it works like a charm, it loads
all the images in less than 3 seconds. It's perfect for me.It's not
good enough! You wanted to prove that pascal is faster then a
scripting language. Here is your chance.  
Now seriously, you should try @hukka's method, it's really
fast(windows only though). Please do the following:
1. Install GDIPlus from OPM(just added)
2. Install BGRABitmap if needed
3. Compile then run attached project
4. Download sample jpg image(30 Mb) from https://sample-
videos.com/download-sample-jpg-image.php
At my side the 30 Mb image is loaded in 0.663 sec, which is ~5 times
faster then the native solution presented by @wp in reply #5. More
over it can load many image formats not just jpgs. Combine this method
with your threaded solution and tell us the result. Since image
processing is a CPU intensive task, it makes no sense to start more
threads then your CPU/Core count. Usually 3 threads are not enough
though.

@hukka
Very nicely done!

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domasz · 2023-04-13 08:14

While Javascript is single-threaded, the web browser (Electron,
Firefox, Chrome...) is not. It uses your CPU, GPU and lots of RAM for
caching.
Javascript is not decoding images, the browser is. And it downloads
and decodes images using many threads and many internet connections.

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balazsszekely · 2023-04-13 08:44

@domasz
QuoteWhile Javascript is single-threaded, the web browser (Electron,
Firefox, Chrome...) is not. It uses your CPU, GPU and lots of RAM for
caching.
Javascript is not decoding images, the browser is. And it downloads
and decodes images using many threads and many internet
connections.OK! Then let's forget about Javascript for a minute and
compare the mighty browser(I suppose the rendering engine is coded in
c++ ) with @hukka's example. Tested with Firefox 112.0(64 bit) vs.
Lazarus Trunk/FPC 3.2.2(64 bit) and the results are very similar,
Firefox it's slightly faster but not by much, tested with the 30 Mb
jpeg(see above).

PS: Is pascal a good programming language? According to John Carmack
it is: https://youtu.be/I845O57ZSy4?t=5743 
PS: Also about javascript(LMAO):
https://www.youtube.com/watch?v=I845O57ZSy4&t=1115s

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KodeZwerg · 2023-04-13 09:23

@GetMem, cool your loading method! I compared against ImageMagick,
yours beat it 3x faster!

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balazsszekely · 2023-04-13 09:33

Quote from: KodeZwerg on April 13, 2023, 11:23:42 am@GetMem, cool your
loading method! I compared against ImageMagick, yours beat it 3x
faster!
Thank you, but all credits goes to @hukka. I only created a small demo
application according to the code posted by him.

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loaded · 2023-04-13 11:00

The Google Picasa program is the expert in this business.
It makes loading, viewing and zooming the image surprisingly fast.
In fact, it would be great if the experts of the business examine and
analyze this software.

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domasz · 2023-04-13 11:20

I tested this lib a while ago and was the fastest JPEG decoder for
Delphi. But won't compile in Lazarus:
http://www.marktg.com/jpegdec/

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balazsszekely · 2023-04-13 12:48

Quote from: domasz on April 13, 2023, 01:20:06 pmI tested this lib a
while ago and was the fastest JPEG decoder for Delphi. But won't
compile in Lazarus:
http://www.marktg.com/jpegdec/
Challenge accepted. JpegDec(Delphi 11) vs. GDIPlus(Lazarus/FPC), same
10 MB jpg image. I would say the two are very similar in performance.

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KodeZwerg · 2023-04-13 12:58

Now add libjpeg-turbo to your test candidates and we are done

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balazsszekely · 2023-04-13 13:00

Quote from: KodeZwerg on April 13, 2023, 02:58:53 pmNow add libjpeg-
turbo to your test candidates and we are done
Do you have a demo somewhere? Lazarus or D. it does not matter.

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domasz · 2023-04-13 13:15

Quote from: GetMem on April 13, 2023, 02:48:27 pmChallenge accepted.
JpegDec(Delphi 11) vs. GDIPlus(Lazarus/FPC), same 10 MB jpg image. I
would say the two are very similar in performance.
Are you measuring decoding time only? Excluding time needed to load
from disk? Also multiply this by 1000 images and the difference is
already noticable.

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phoenix27 · 2023-04-13 13:19

OMG hukka the code you shared is blazing fast!!! Thank you! Get mem i
downloaded the 30MB image and added it, well to load that single image
it took about 6 sec.  With GDI it showed up immediately, and i really
mean it. What a shame that GDI is windows only. You know, up to a few
weeks ago i was quite happy with linux mint, then i installed lazarus
to try free pascal but i wasnt so happy because from the installation
on it gave me all sorts of problems, sometimes it crashed out of the
blue, sometimes it wouldn't start at all giving me some strange errors
and so on. So, knowing that object pascal  is mainly a windows thing,
i switched back to windows 7 and voila', it works really well now.
Get mem i know that pascal is faster than javascript, its speed is
comparable to that of c++. I just couldn't understand why the loading
of images was so slow. But now i know why. Im' happy because now i can
create my little apps without having to rely on a server/client
architecture(the browser and nodejs) or electron. It's a shame that
pascal doesn't get the attention that should deserve. Faster,
efficient memory management, my app in electron at this moment
occupies 300MB, just for showing some pictures, pascal instead is
26MB. People are sheeple ahahaha

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KodeZwerg · 2023-04-13 13:35

Quote from: GetMem on April 13, 2023, 03:00:37 pmQuote from: KodeZwerg
on April 13, 2023, 02:58:53 pmNow add libjpeg-turbo to your test
candidates and we are done
Do you have a demo somewhere? Lazarus or D. it does not matter.
A copy of old headers ( Delphi compatible, Lazarus needs love   ) and
binary lib ( Windows ) files added.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses 
cgJpeg; var  jpg: TJpegImage;begin  jpg := TJpegImage.Create;  try   
jpg.LoadFromFile('jpegFile.jpg');    // do something with it like   
Image1.Picture.Bitmap.Canvas.Draw(0, 0, jpg);  finally    jpg.Free; 
end;end;

----------------------------------------------------------------------
KodeZwerg · 2023-04-13 14:01

Quote from: domasz on April 13, 2023, 03:15:22 pmQuote from: GetMem on
April 13, 2023, 02:48:27 pmChallenge accepted. JpegDec(Delphi 11) vs.
GDIPlus(Lazarus/FPC), same 10 MB jpg image. I would say the two are
very similar in performance.
Are you measuring decoding time only? Excluding time needed to load
from disk? Also multiply this by 1000 images and the difference is
already noticable.
I do fully second your statement.
For benchmarking the jpeg file should be loaded into a stream, from
that stream some thousand times a jpeg decoding (LoadFromStream)
should be measured and the average time should be the result.
Loading file from disk and displaying shall be excluded.

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balazsszekely · 2023-04-13 15:38

@domasz, @KodeZwerg
Are you aware that with your latest comment basically you auto
assigned yourself to do the testing?   I'm not interested in such an
extensive/detailed test, please let me know the result. Currently I' m
working on a cross platform solution, which will be able to load
multiple image format not just jpg(like GDI does on windows), only in
a cross platform way. I believe OpenGl is the correct approach, I'm
not sure yet though.

@KodeZwerg
Thanks for the headers. I will take a look later.

@phoenix27
So how fast is your threaded version now? Also can you share the
project? If you don't want to is perfectly fine.
QuoteIt's a shame that pascal doesn't get the attention that should
deserve. Faster, efficient memory management, my app in electron at
this moment occupies 300MB, just for showing some pictures, pascal
instead is 26MB. People are sheeple ahahaha
In my opinion the main issue with pascal is not performance, but the
lack of available jobs + students no longer learn the language. The
vast majority of pascal programmers are over 40, 50 maybe?, I'm not
sure. Pascal is not dying, but the programmers will at some point.

----------------------------------------------------------------------
lainz · 2023-04-13 15:48

Quote from: GetMem on April 13, 2023, 05:38:34 pmIn my opinion the
main issue with pascal it's not performance, but the lack of available
jobs + students no longer learn the language. The vast majority of
pascal programmers are over 40, 50 maybe?, I'm not sure. Pascal is not
dying, but the programmers will at some point.
I'm 33 and I have a Pascal job, but here in my country few
Universities teach pascal, I learned Pascal by myself. I get the job
thanks to this forum and because I'm one of the authors of
BGRAControls. I'm very happy

----------------------------------------------------------------------
balazsszekely · 2023-04-13 15:53

Quote from: lainz on April 13, 2023, 05:48:40 pmQuote from: GetMem on
April 13, 2023, 05:38:34 pmIn my opinion the main issue with pascal
it's not performance, but the lack of available jobs + students no
longer learn the language. The vast majority of pascal programmers are
over 40, 50 maybe?, I'm not sure. Pascal is not dying, but the
programmers will at some point.
I'm 33 and I have a Pascal job, but here in my country few
Universities teach pascal, I learned Pascal by myself. I get the job
thanks to this forum and because I'm one of the authors of
BGRAControls. I'm very happy
I know @lainz, but you are the exception not the rule. I'm glad to
hear that younger people still learn Pascal and there are available
jobs out there. 

PS: 🇦🇷 is a cool country if universities still teach Pascal. Big like!

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hukka · 2023-04-13 19:04

Correction to my previous posts, I use turbojpeg, not libjpeg-turbo in
my current project.
I've attached the relevant header, 64-bit DLL (can't include the
32-bit DLL due to attachment filesize limit) and the JPEG loader unit
from my image viewer (TBitmap32=TBGRABitmap, sorry for the
idiosyncracy).

----------------------------------------------------------------------
lainz · 2023-04-14 01:01

Quote from: lainz on April 13, 2023, 05:48:40 pmQuote from: GetMem on
April 13, 2023, 05:38:34 pmIn my opinion the main issue with pascal
it's not performance, but the lack of available jobs + students no
longer learn the language. The vast majority of pascal programmers are
over 40, 50 maybe?, I'm not sure. Pascal is not dying, but the
programmers will at some point.
I'm 33 and I have a Pascal job, but here in my country few
Universities teach pascal, I learned Pascal by myself. I get the job
thanks to this forum and because I'm one of the authors of
BGRAControls. I'm very happy

Thanks! I've seen a Pascal online course in Spanish as well. Is a paid
course but looks very complete. I did a gift of this course to a
friend in the company I work he is tech support but is learning to
program in Pascal. He is like 10 years younger than me.

The owner of the company where I work is Pascal programmer as well and
is my friend too. He knows a lot of everything from backend to
frontend to Android and web, databases. I've learned a lot of that as
well.

----------------------------------------------------------------------
circular · 2023-04-14 19:27

Not sure if that will be of use but there is BGRAThumbnail unit in
BGRABitmap that allows to quickly load a preview, with less quality, a
thumbnail of given size.

About hukka suggestion to use Gdi+ that seems a good idea to do on
Windows. This could be a possible optimization of BGRABitmap library.