Hi guys,
I just finished (a beta) of a collage app for Aurawin. I'm seeing a huge load on my servers when scaling images using the Image factory classes for JPEG, and PNG.
Prefix:
6 Core AMD 64 32GB RAM Ubuntu 12.10 x64
8 Core AMD 64 32GB RAM Ubuntu 12.10 x64
FPC/Lazarus daily svn/trunk
Overview:
1.) end-user grabs references to files (stored on my server) 2.) back-end core object scales camera photos to something more net friendly 512px max to scale.
3.) server streams photos back to client over the web and 4.) server assembles XML stream of Mime encoded file data for things like https://aurawin.com/cb?3
Specifics
The pics in this sample take about 30 seconds to go from their originals to 512px. The app waits for the collage to save to the cloud. The problem gets worse for larger collages with more images.
iX,iY are no larger than 512
class function Image.Transform(Stream:TStream; var
sContentType,srcKind,dstKind:string; var iX,iY:Integer):boolean;
var
FReader : TFPCustomImageReader;
FWriter : TFPCustomImageWriter;
cReader : TFPCustomImageReaderClass;
cWriter : TFPCustomImageWriterClass;
Factor : Double;
FTransparent : boolean;
dstImg : TFPMemoryImage;
srcImg : TFPMemoryImage;
srcCanvas : TFPImageCanvas;
dstCanvas : TFPImageCanvas;
procedure FreeImageData;
begin
if (srcCanvasnil) then
srcCanvas.Free();
if (dstCanvasnil) then
dstCanvas.Free();
if (FReadernil) then
FReader.Free();
if FWriternil then
FWriter.Free();
if srcImgnil then
srcImg.Free();
if dstImgnil then
dstImg.Free();
end;
begin
Result:=false;
if SameText(srcKind,Image.Kind.GIF.Name) then begin
sContentType:=hHTTP.ctPNG;
dstKind:=Image.Kind.PNG.Name;
FTransparent:=true;
end else if SameText(srcKind,Image.Kind.PNG.Name) then begin
dstKind:=Image.Kind.PNG.Name;
FTransparent:=true;
end else begin
sContentType:=hHTTP.ctJPG;
dstKind:=Image.Kind.JPG.Name;
FTransparent:=false;
end;
cReader:=FPImage.ImageHandlers.ImageReader[srcKind];
cWriter:=FPImage.ImageHandlers.ImageWriter[dstKind];
dstCanvas:=nil; srcCanvas:=nil; FReader:=nil; FWriter:=nil;
srcImg:=nil; dstImg:=nil;
Result:=(cReadernil) and (cWriternil);
if Result then begin
Try
FReader:=cReader.Create();
FWriter:=cWriter.Create();
if SameText(dstKind,Image.Kind.PNG.Name) then begin
TFPWriterPNG(FWriter).Indexed:=false;
TFPWriterPNG(FWriter).UseAlpha:=true;
end;
srcImg:=TFPMemoryImage.Create(0,0);
srcImg.UsePalette:=false;
Stream.Position:=0;
Try
srcImg.LoadFromStream(Stream,FReader);
Stream.Position:=0;
if (srcImg.Width>=srcImg.Height) then begin
Factor:=iX/srcImg.Width;
end else begin
Factor:=iY/srcImg.Height;
end;
if (srcImg.Width>iX) or (srcImg.Height>iY) then begin
if FTransparent then begin
if SameText(srcKind,Image.Kind.GIF.Name) then begin
FTransparent:=TFPReaderGIF(FReader).Transparent;
TFPWriterPNG(FWriter).UseAlpha:=true;
end;
end;
iX:= Round(srcImg.Width * Factor);
iY:= Round(srcImg.Height * Factor);
dstImg:=TFPMemoryImage.Create(iX,iY);
dstImg.UsePalette:=false;
dstCanvas:=TFPImageCanvas.create(dstImg);
dstCanvas.StretchDraw(0,0,iX,iY,srcImg);
Stream.Size:=0;
dstImg.SaveToStream(Stream,FWriter);
Stream.Position:=0;
Result:=true;
end;
Except
Stream.Size:=0;
Stream.Position:=0;
Result:=false;
end;
Finally
FreeImageData();
end;
end;
end;Further, when a user views images via my preview app, I don't send the originals, I scale those too using the same methods. The speed is killing my server's performance.
Does anyone have any idea how to speed up the underlining code?