I'm using the following code to load a .jpg image into a TBitmap object, but when I load a large .jpg file of size 50.000 x 40.000 pixels, I get an "out of memory" failure.
procedure LoadJPEG(Bmp: TBitMap; fName: string);
var
JPEG: TJPEGImage;
begin
JPEG := TJPEGImage.Create;
try
JPEG.LoadFromFile(fName);
with Bmp do
begin
Assign(JPEG);
end;
finally
JPEG.Free;
end;
end;
How to improve the code above to load larger images into my TBitmap object?
Related
Follwing on:
How to load large bitmap in FMX (fire monkey)
I have come to a need to draw whats on TBitmapSurface on the FMX.Graphics.TBitmap, i have found a lot of answer regarding this on the web, but they are either in VLC instead of FMX or their goal is saving and loading instead of drawing on a TBitmap, which is why i asked a new question here.
Now here is my current code for loading my image on the TBitmapSurface :
var
bitmapSurf: TBitmapSurface;
path: string;
begin
path := 'image.jpg';
bitmapSurf := TBitmapSurface.Create;
TBitmapCodecManager.LoadFromFile(path, bitmapSurf);
end;
Now after searching for a bit i found that i can use Scanline on the TBitmapSurface, but i didn't know how to use it to draw on the TBitmap, on the web some people had used TBitmap.canvas.draw, but such a thing doesn't exist on the FMX!.
In the end my goal is to draw a very large image (1000*16000) which is loaded in the TBitmapSurface on more then 1 TBitmap (because TBitmap doesn't support more then 8192px and my height is 16000px, i need to draw this on two TBitmap).
I am using Delphi 10.2.3.
Thanks.
You can split the large image (from a file) to two TImage components as follows
Load the image from file to a TBitmapSurface as you already do in your code.
Then create another TBitmapSurface and set its size to the half of the large one. Copy the first half of the large image to this surface and assign it to Image1.Bitmap. Then copy the latter half to this surface and assign that to Image2.Bitmap.
var
srce, dest: TBitmapSurface;
path: string;
scan: integer;
w, h1, h2: integer;
begin
path := 'C:\tmp\Imgs\res.bmp';
srce := TBitmapSurface.Create;
try
TBitmapCodecManager.LoadFromFile(path, srce);
dest := TBitmapSurface.Create;
try
// first half
w := srce.Width;
h1 := srce.Height div 2;
dest.SetSize(w, h1, TPixelFormat.RGBA);
for scan := 0 to h1-1 do
Move(srce.Scanline[scan]^, TBitmapSurface(dest).Scanline[scan]^, srce.Width * 4);
Image1.Bitmap.Assign(dest);
// second half
h2 := srce.Height - h1;
dest.SetSize(w, h2, TPixelFormat.RGBA);
for scan := h1 to srce.Height-1 do
Move(srce.Scanline[scan]^, TBitmapSurface(dest).Scanline[scan-h1]^, srce.Width * 4);
Image2.Bitmap.Assign(dest);
finally
dest.Free;
end;
finally
srce.Free;
end;
I need a e method which compares content of two files together, files can be BMP, JPEG, PNG, TIF
I tried this
procedure TForm1.Button1Click(Sender: TObject);
var
f1, f2 : TFileStream;
Bytes1: TBytes;
Bytes2: TBytes;
i: integer;
s: booleAN;
begin
f1 := TFileStream.Create('C:\Output\Layout 1.JPG' , fmOpenRead);
f2 := TFileStream.Create('C:\Data\Layout 1.JPG' , fmOpenRead );
if f1.Size <> f2.Size then
begin
ShowMessage('size');
exit;
end;
SetLength(Bytes1, f1.Size);
f1.Read(Bytes1[0], f1.Size);
SetLength(Bytes2, f2.Size);
f2.Read(Bytes2[0], f2.Size);
s:= true;
for I := 1 to length(Bytes1) do
begin
if Bytes1[i] <> Bytes2[i] then
begin
s := false;
Exit;
end;
end;
if s then
ShowMessage('same');
end;
but this is not working fine for me my files are both the same in content but their size are different in 2 byte.
one of the files is the on that I have to give to user the other one is the files that user is opening the same file and make a copy of it, so why they are 2 byte different i have no idea but they should be away to compare content of these files
The code has one error. Dynamic arrays are zero based so the loop should be:
for I := 0 to high(Bytes1) do
The code is very inefficient. It should not read all the content at once. And you should use CompareMem to compare blocks of memory.
You say that the files have different size, but you expect them to compare equal. Well, that makes no sense. Your code explicitly checks that the sizes match, as it should.
Opening and reading a JPEG file will modify the content because JPEG is a lossy compression algorithm.
Your subject suggests that you wish to compare PowerPoint files but the files are in fact JPEG images.
If you are going to compare JPEGs you probably need to include a range, something like
Const
DELTA = 2 ;
if (Bytes1[i] - Bytes2[i] > DELTA) OR (Bytes1[i] - Bytes2[i] < -DELTA) then
In Delphi I have an unknown number of image file names stored in a details table. These image files can be Bitmaps, Jpegs, PNGS and ICO files.
What's the paradigm / best practice to load and display those in a listview or a listbox on the go?
I take it I would somehow need to load those to a ImageList in OnBeforeScroll event of a master table and then assign that to a listview. Database components used are dbGO.
I only need to display thumbnails of predefined size (in a VCL program).
The simplest method is to use TPicture, since the loading of different graphic formats is already implemented and you do have to care about different image classes .
You have to ensure that the required units are included in the with uses so here e.g. jpeg, gifimg, and pngimg.
After loading with TPicture.LoadFromFile the images are painted, centered and scaled, on a prepared Bitmap with the dimensions of the Imagelist.
Last step is simply to call teh AddBitmap procedure with the Bitmap and nil for the mask.
// make sure you included the needed units
// uses pngImage,jpeg,gifimg;
Procedure LoadImagesFromDataset2ImageList(il: TImageList; DS: TDataset; const FileFieldname: String);
var
P: TPicture;
bmp: TBitmap;
Function CalcRectAndPrepare: TRect; // calculate Rect for here centered/streched output
var // and fill the bitmap with the desired beckground color
f: Double;
begin
bmp.Canvas.Brush.Color := clWhite;
bmp.Canvas.FillRect(Rect(0, 0, bmp.Width, bmp.Height));
if P.Width > P.Height then
f := bmp.Width / P.Width
else
f := bmp.Height / P.Height;
Result.Left := Round(bmp.Width - P.Width * f) div 2;
Result.Top := Round(bmp.Height - P.Height * f) div 2;
Result.Right := bmp.Width - Result.Left;
Result.Bottom := bmp.Height - Result.Top;
end;
begin
P := TPicture.Create;
bmp := TBitmap.Create;
try
bmp.Width := il.Width;
bmp.Height := il.Height;
DS.First;
while not DS.Eof do
begin
if FileExists(DS.Fieldbyname(FileFieldname).asString) then
begin
P.LoadFromFile(DS.Fieldbyname(FileFieldname).asString);
bmp.Canvas.StretchDraw(CalcRectAndPrepare, P.Graphic);
il.Add(bmp, nil);
end;
DS.Next;
end;
finally
P.Free;
bmp.Free;
end;
end;
"Unknown number" sounds like there may be a huge number of images. So pre-rendered thumbnails would be very helpful. If your application can create thumbnails for all images and keep them in a separate database this would reduce the CPU resource usage for shrinking them. And you could reference the thumbnail database from your master database.
One thing I would check if RAM could be a limitation is how many instances of the actual thumbnail will be created in your application, for example if you load 1000 database records which all refer to the same thumbnail, does the database access component allocate 1000 image objects (using 1000 times more RAM than needed) or only one, which is referenced 1000 times. Also the de-allocation of the image data is important.
This code works on the PngImage component (from G.Daud). Now it doesn't compile after PngImage is replaced with PngComponents for D7 (http://code.google.com/p/cubicexplorer/downloads/list).
function Bmp32ToPng(bmp: TBitmap): TPngObject;
var
x, y: integer;
src, dst: PngImage.pByteArray;
begin
Result:= nil;
if bmp.PixelFormat<>pf32bit then
Exit;
Result:= TPngObject.CreateBlank(COLOR_RGBALPHA, 8, bmp.Width, bmp.Height);
Result.Canvas.Draw(0, 0, bmp);
for y:= 0 to bmp.Height-1 do begin
src:= bmp.ScanLine[y];
dst:= Result.AlphaScanLine[y];
for x:= 0 to bmp.Width-1 do
dst[x]:= src[x*4+3];
end;
end;
The Createblank method does not exist in PngComponents. It can't be replaced with a simple Create then setting Width/height. Width/height are R/O in PngComponents.
How to convert 32bpp BMP (e.g. got from shell32.dll) to PNG?
GraphicEx and PngComponents and pngimage are conflicting. To solve it:
1) always put them in uses clause in specific order - first - GraphicEx or PngComponents, last - pngimage.
2) build Project. It is not enough to run (or compile) project after uses clause was changed.
PS) pngimage installed with PNGcomponent package, BUT this version is outdated
I am trying to convert a bitmap file to rtf using Delphi 2007.
I used below code for conversion.
function BitmapToRTF(pict: TBitmap): string;
var
bi, bb, rtf: string;
bis, bbs: Cardinal;
achar: ShortString;
hexpict: string;
I: Integer;
begin
GetDIBSizes(pict.Handle, bis, bbs);
SetLength(bi, bis);
SetLength(bb, bbs);
GetDIB(pict.Handle, pict.Palette, PChar(bi)^, PChar(bb)^);
rtf := '{\rtf1 {\pict\dibitmap0 ';
SetLength(hexpict, (Length(bb) + Length(bi)) * 2);
I := 2;
for bis := 1 to Length(bi) do
begin
achar := Format('%x', [Integer(bi[bis])]);
if Length(achar) = 1 then
achar := '0' + achar;
hexpict[I - 1] := achar[1];
hexpict[I] := achar[2];
Inc(I, 2);
end;
for bbs := 1 to Length(bb) do
begin
achar := Format('%x', [Integer(bb[bbs])]);
if Length(achar) = 1 then
achar := '0' + achar;
hexpict[I - 1] := achar[1];
hexpict[I] := achar[2];
Inc(I, 2);
end;
rtf := rtf + hexpict + ' }}';
Result := rtf;
end;
Now my problem is i was not able to view the image in MS Word or Viewer.
But i can view the image in word pad.
Please suggest me in solving this problem.
I think the problem is that the Word implementation for RTF rendering asks for more information than the Wordpad's one (I think that for security reasons -avoid overflow attacks-), but this is pure speculation I must confess.
Try being accurate when describing your bitmap info: for example if the bitmap is 32-bit use \wbmbitspixel32, put the width and height in your rtf encoding with \picw and \pich, etc. May be you have luck with that.
Here is an example of this:
http://www.scribd.com/doc/25967552/Rtf1-Ansi-Ansicpg1252-Uc2-Deff0-Deflang1033-Fonttbl-f0-Froman-Fcharset0-Fprq2-Panose-02020603050405020304-Times-New-Roman-f1-Fswiss-Fchar
How can you convert an image to a textfile?
RTF is RichtTextFormat i guess?
I would take the bmp and put it with the Microsoft Word API into a Document and save the document was rtf.
Tobi
If you want to view the image in MS Word or Word Viewer, convert the image to EMF file and embed it inside the RTF tags. (Note: here you cant view the image in Wordpad)
{\rtf1 {\pict\emfblif <emf source> }}
If you want to view the image in Wordpad, convert the image into bitmap and embed it inside the RTF tags.
{\rtf1 {\pict\dibitmap0 <bitmap source> }}
I dont know why this happens.