I'm using Delphi 10.4.2 and I'm trying to find a way to scale images that mantains the image quality and doesn't request external libraries.
This is what I tried, you can find the two tests in {$REGION}:
procedure TFrmTestGenImg.Test;
var
LOldWidth, LOldHeight, LNewWidth, LNewHeight: integer;
LImageNameIn, LImageNameOut, LExt: string;
LClass: TGraphicClass;
LImageIn, LImageOut: TGraphic;
LBitmap, LResized: TBitmap;
begin
// Original image: 1366 x 768
LOldWidth := 1366;
LOldHeight := 768;
LNewWidth := 800;
LNewHeight := 449;
LImageNameIn := 'C:\temp\Input.png';
LImageNameOut := 'C:\temp\Output_' + FormatDateTime('yyyy.mm.dd hh.nn.ss.zzz', Now) + '.png';
LExt := TPath.GetExtension(LImageNameIn);
Delete(LExt, 1, 1);
if (CompareText(LExt, 'bmp') = 0) then
LClass := TBitmap
else if (CompareText(LExt, 'gif') = 0) then
LClass := TGIFImage
else
LClass := TWICImage;
LImageIn := LClass.Create;
try
LImageOut := LClass.Create;
try
LImageIn.Transparent := True;
LImageIn.LoadFromFile(Trim(LImageNameIn));
LBitmap := TBitmap.Create;
try
LBitmap.PixelFormat := pf24bit;
LBitmap.Assign(LImageIn);
{$REGION '1st test'}
LBitmap.Canvas.StretchDraw(
Rect(0, 0, LNewWidth, LNewHeight),
LImageIn); // -> poor quality
LBitmap.SetSize(LNewWidth, LNewHeight);
LImageOut.Assign(LBitmap);
{$ENDREGION}
{$REGION '2nd test'}
LResized := TBitmap.Create;
try
LResized.Assign(LBitmap);
LResized.Width := LNewWidth;
LResized.Height := LNewHeight;
GraphUtil.ScaleImage(LBitmap, LResized, (LNewWidth/LOldWidth)); // -> empty image
LResized.SetSize(LNewWidth, LNewHeight);
LImageOut.Assign(LResized);
finally
LResized.Free;
end;
{$ENDREGION}
if LImageIn is TWICImage then
begin
if (CompareText(LExt, 'jpg') = 0) or (CompareText(LExt, 'jpeg') = 0) then
TWICImage(LImageOut).ImageFormat := wifJpeg
else
TWICImage(LImageOut).ImageFormat := TWICImage(LImageIn).ImageFormat;
end;
LImageOut.SaveToFile(LImageNameOut);
finally
LBitmap.Free;
end;
finally
LImageOut.Free;
end;
finally
LImageIn.Free;
end;
end;
As you can see, for the second test I used GraphUtil.ScaleImage but the output is an empty image, so I'm not sure I used it correctly, unfortunately I haven't found any example of this method..
procedure ResizeBitmap(const Bitmap: TBitmap; const NewWidth, NewHeight: integer);
var
Factory: IWICImagingFactory;
Scaler: IWICBitmapScaler;
Source : TWICImage;
begin
Source := TWICImage.Create;
try
Factory := TWICImage.ImagingFactory;
Source.Assign(Bitmap);
Factory.CreateBitmapScaler(Scaler);
Scaler.Initialize(Source.Handle, NewWidth, NewHeight, WICBitmapInterpolationModeHighQualityCubic);
Source.Handle := IWICBitmap(Scaler);
Bitmap.Assign(Source);
Scaler := nil;
Factory := nil;
finally
Source.Free;
end;
end;
A little simpler
procedure ResizeBitmap(const Bitmap: TBitmap; const NewWidth, NewHeight: integer);
Var vImage,v2: TWICImage;
begin
vImage := TWICImage.Create;
try
vImage.Assign(Bitmap);
v2 := vImage.CreateScaledCopy(NewWidth, NewHeight, wipmHighQualityCubic);
Bitmap.Assign(v2);
finally
v2.Free;
vImage.Free;
end;
end;
Related
I'm trying to link a database image to a TDBImage component in delphi 10 but it keeps giving me the error that my specified field cannot be found even though there aren't any syntax errors.
This is the code I'm using.
function TForm1.JPEGStartBlob(fPic: TBlobField): integer;
var
bS: TADOBlobStream;
buffer: Word;
hx: string;
begin
Result := -1;
bS := TADOBlobStream.Create(fPic, bmRead);
try
while (Result = -1) and (bS.Position + 1 < bS.Size) do
begin
bS.ReadBuffer(buffer, 1);
hx := IntToHex(buffer, 2);
if hx = 'FF' then
begin
bS.ReadBuffer(buffer, 1);
hx := IntToHex(buffer, 2);
if hx = 'D8' then
Result := bS.Position - 2
else if hx = 'FF' then
bS.Position := bS.Position - 1;
end;
end;
finally
bS.Free;
end;
end;
procedure TForm1.ShowImage(Sender: TObject);
var
bsImage : TADOBlobStream;
jImage : TJPEGImage;
begin
bsImage := TADOBlobStream.Create(adoLodgeI.FieldByName('Image') // this is the field that can't be
// found
AS TBlobField, bmRead);
try
bsImage.Seek(JPEGStartBlob(adoLodgeI.FieldByName('Image') AS TBlobField),
soFromBeginning);
jImage := TJPEGImage.Create;
try
jImage.LoadFromStream(bsImage);
dbiLodge1.Picture.Graphic := jImage;
finally
jImage.Free;
end;
finally
bsImage.Free;
end;
end;
If anyone can help it will be much appreciated.
You can use TWICImage and then you can just assign it a the TDBImage.Picture directly
Var
AStream: TMemoryStream;
APic: TWICImage;
begin
AStream := TMemoryStream.Create;
try
// Here "Data" is a BlobField
AStream:= TMemoryStream(TPics.CreateBlobStream(TPics.FieldByName('Data'), bmRead));
AStream.Position:= 0;
APic := TWICImage.Create;
try
APic.LoadFromStream(AStream);
DBImage1.Picture.Assign(APic);
finally
APic.Free;
end;
finally
AStream.Free;
end;
end;
Works with *.jpeg;*.jpg;*.png;*.bmp;*.ico images and you don't need to worry about if the image is a TJPEGImage or not.
For full screenshots, I use this code:
form1.Hide;
sleep(500);
bmp := TBitmap.Create;
bmp.Height := Screen.Height;
bmp.Width := Screen.Width;
DCDesk := GetWindowDC(GetDesktopWindow);
BitBlt(bmp.Canvas.Handle, 0, 0, Screen.Width, Screen.Height, DCDesk, 0, 0, SRCCOPY);
form1.Show ;
FileName := 'Screenshot_'+FormatDateTime('mm-dd-yyyy-hhnnss',now());
bmp.SaveToFile(Format('C:\Screenshots\%s.bmp', [FileName]));
ReleaseDC(GetDesktopWindow, DCDesk);
bmp.Free;
How can I convert that to take a screenshot of only the active window.
First of all you have to get the right window. As sharptooth already noted you should use GetForegroundWindow instead of GetDesktopWindow. You have done it right in your improved version.
But then you have to resize your bitmap to the actual size of the DC/Window. You haven't done this yet.
And then make sure you don't capture some fullscreen window!
When I executed your code, my Delphi IDE was captured and as it is on fullscreen by default, it created the illusion of a fullscreen screenshot. (Even though your code is mostly correct)
Considering the above steps, I was successfully able to create a single-window screenshot with your code.
Just a hint: You can GetDC instead of GetWindowDC if you are only interested in the client area. (No window borders)
EDIT: Here's what I made with your code:
You should not use this code! Look at the improved version below.
procedure TForm1.Button1Click(Sender: TObject);
const
FullWindow = True; // Set to false if you only want the client area.
var
hWin: HWND;
dc: HDC;
bmp: TBitmap;
FileName: string;
r: TRect;
w: Integer;
h: Integer;
begin
form1.Hide;
sleep(500);
hWin := GetForegroundWindow;
if FullWindow then
begin
GetWindowRect(hWin,r);
dc := GetWindowDC(hWin) ;
end else
begin
Windows.GetClientRect(hWin, r);
dc := GetDC(hWin) ;
end;
w := r.Right - r.Left;
h := r.Bottom - r.Top;
bmp := TBitmap.Create;
bmp.Height := h;
bmp.Width := w;
BitBlt(bmp.Canvas.Handle, 0, 0, w, h, DC, 0, 0, SRCCOPY);
form1.Show ;
FileName := 'Screenshot_'+FormatDateTime('mm-dd-yyyy-hhnnss',now());
bmp.SaveToFile(Format('C:\Screenshots\%s.bmp', [FileName]));
ReleaseDC(hwin, DC);
bmp.Free;
end;
EDIT 2: As requested I'm adding a better version of the code, but I'm keeping the old one as a reference. You should seriously consider using this instead of your original code. It'll behave much nicer in case of errors. (Resources are cleaned up, your form will be visible again, ...)
procedure TForm1.Button1Click(Sender: TObject);
const
FullWindow = True; // Set to false if you only want the client area.
var
Win: HWND;
DC: HDC;
Bmp: TBitmap;
FileName: string;
WinRect: TRect;
Width: Integer;
Height: Integer;
begin
Form1.Hide;
try
Application.ProcessMessages; // Was Sleep(500);
Win := GetForegroundWindow;
if FullWindow then
begin
GetWindowRect(Win, WinRect);
DC := GetWindowDC(Win);
end else
begin
Windows.GetClientRect(Win, WinRect);
DC := GetDC(Win);
end;
try
Width := WinRect.Right - WinRect.Left;
Height := WinRect.Bottom - WinRect.Top;
Bmp := TBitmap.Create;
try
Bmp.Height := Height;
Bmp.Width := Width;
BitBlt(Bmp.Canvas.Handle, 0, 0, Width, Height, DC, 0, 0, SRCCOPY);
FileName := 'Screenshot_' +
FormatDateTime('mm-dd-yyyy-hhnnss', Now());
Bmp.SaveToFile(Format('C:\Screenshots\%s.bmp', [FileName]));
finally
Bmp.Free;
end;
finally
ReleaseDC(Win, DC);
end;
finally
Form1.Show;
end;
end;
Your code could be a lot simpler. When you have decided on which form you want to save, try the code I use:
procedure SaveFormBitmapToBMPFile( AForm : TCustomForm; AFileName : string = '' );
// Copies this form's bitmap to the specified file
var
Bitmap: TBitMap;
begin
Bitmap := AForm.GetFormImage;
try
Bitmap.SaveToFile( AFileName );
finally
Bitmap.Free;
end;
end;
This combines all the approaches described so far. It also handles multiple-monitor scenarios.
Pass in the kind of screenshot you want, and a TJpegImage, and it will assign your requested screenshot to that image.
///////////
uses
Jpeg;
type //define an ENUM to describe the possible screenshot types.
TScreenShotType = (sstActiveWindow, sstActiveClientArea,
sstPrimaryMonitor, sstDesktop);
///////////
procedure TfrmMain.GetScreenShot(shotType: TScreenShotType;
var img: TJpegImage);
var
w,h: integer;
DC: HDC;
hWin: Cardinal;
r: TRect;
tmpBmp: TBitmap;
begin
hWin := 0;
case shotType of
sstActiveWindow:
begin
//only the active window
hWin := GetForegroundWindow;
dc := GetWindowDC(hWin);
GetWindowRect(hWin,r);
w := r.Right - r.Left;
h := r.Bottom - r.Top;
end; //sstActiveWindow
sstActiveClientArea:
begin
//only the active client area (active window minus title bars)
hWin := GetForegroundWindow;
dc := GetDC(hWin);
GetWindowRect(hWin,r);
w := r.Right - r.Left;
h := r.Bottom - r.Top;
end; //sstActiveClientArea
sstPrimaryMonitor:
begin
//only the primary monitor. If 1 monitor, same as sstDesktop.
hWin := GetDesktopWindow;
dc := GetDC(hWin);
w := GetDeviceCaps(DC,HORZRES);
h := GetDeviceCaps(DC,VERTRES);
end; //sstPrimaryMonitor
sstDesktop:
begin
//ENTIRE desktop (all monitors)
dc := GetDC(GetDesktopWindow);
w := Screen.DesktopWidth;
h := Screen.DesktopHeight;
end; //sstDesktop
else begin
Exit;
end; //case else
end; //case
//convert to jpg
tmpBmp := TBitmap.Create;
try
tmpBmp.Width := w;
tmpBmp.Height := h;
BitBlt(tmpBmp.Canvas.Handle,0,0,tmpBmp.Width,
tmpBmp.Height,DC,0,0,SRCCOPY);
img.Assign(tmpBmp);
finally
ReleaseDC(hWin,DC);
FreeAndNil(tmpBmp);
end; //try-finally
end;
JCL comes to the rescue once again..
hwnd := GetForegroundWindow;
Windows.GetClientRect(hwnd, r);
JclGraphics.ScreenShot(theBitmap, 0, 0, r.Right - r.Left, r.Bottom - r.Top, hwnd);
// use theBitmap...
Thank you for this useful submission I thought I might make the code offered into a unit to use all over my application, here is the code I have running on DX10.2 Tokyo. Please note the example, watch out for memory leaks.
unit ScreenCapture;
interface
uses Windows, Vcl.Controls, Vcl.StdCtrls, VCL.Graphics,VCL.Imaging.JPEG, VCL.Forms;
function getScreenCapture( FullWindow: Boolean = True ) : TBitmap;
implementation
function getScreenCapture( FullWindow: Boolean ) : TBitmap;
var
Win: HWND;
DC: HDC;
WinRect: TRect;
Width: Integer;
Height: Integer;
begin
Result := TBitmap.Create;
//Application.ProcessMessages; // Was Sleep(500);
Win := GetForegroundWindow;
if FullWindow then
begin
GetWindowRect(Win, WinRect);
DC := GetWindowDC(Win);
end
else
begin
Windows.GetClientRect(Win, WinRect);
DC := GetDC(Win);
end;
try
Width := WinRect.Right - WinRect.Left;
Height := WinRect.Bottom - WinRect.Top;
Result.Height := Height;
Result.Width := Width;
BitBlt(Result.Canvas.Handle, 0, 0, Width, Height, DC, 0, 0, SRCCOPY);
finally
ReleaseDC(Win, DC);
end;
end;
end.
Example :
//Any event or button click, screenCapture is a TBitmap
screenCapture := getScreenCapture();
try
//Do some things with screen capture
Image1.Picture.Graphic := screenCapture;
finally
screenCapture.Free;
end;
Use GetForegroundWindow() instead of GetDesktopWindow().
You'll have to save the handle which GetForegroundWindow() return and pass the saved value into ReleaseDC() - to be sure that GetWindowDC() and ReleaseDC() are called exactly for the same window in case the active window changes between calls.
In case anyone is looking for a more cross-platform solution, this one claims Windows and MacOS-X support:
https://github.com/z505/screenshot-delphi
The shortest version of the Brian Frost code:
Screen.ActiveForm.GetFormImage.SaveToFile(Screen.ActiveForm.Caption+'.bmp');
Just one line of the code (Screenshot of the active window in the MDI application).
i need to convert all pixels of a canvas
found this function after a quick search in google
but dont work correct , but it seems must work good!!
function RGBBitmapTo1Bit(OriginalBitmap : TBitmap) : TBitmap;
var
x, y : integer;
begin
result := TBitmap.Create;
result.width := OriginalBitmap.width;
result.height := OriginalBitmap.height;
for x := 1 to OriginalBitmap.width do
for y := 1 to OriginalBitmap.height do
begin
result.Canvas.Pixels[x, y] := clBlack;
end;
end;
this function dont make any change on the file
for example i used like this
procedure TForm1.Button2Click(Sender: TObject);
var
imgf : TBitmap;
begin
if od1.Execute then
begin
imgf := TBitmap.Create;
imgf.LoadFromFile(od1.FileName);
RGBBitmapTo1Bit(imgf);
imgf.SaveToFile(ExtractFilePath(od1.FileName)+'test.bmp');
end;
but the output and input files are the same!!!
how can i assign a color to a pixel rightly!?
Your code has three problems with it:
Pixels are 0-indexed in both dimensions, so you need to change your loops accordingly.
for x := 0 to OriginalBitmap.width-1 do
for y := 0 to OriginalBitmap.height-1 do
your function DOES NOT modify the original TBitmap, it allocates and modifies a new TBitmap and then returns that to the caller, but the caller is ignoring that new bitmap, expecting the original TBitmap to have been modified instead. You are saving the original TBitmap to file, which is why you don't see any of the pixels changed.
You are leaking memory for both TBitmap objects;
Try this instead:
function RGBBitmapTo1Bit(OriginalBitmap : TBitmap) : TBitmap;
var
x, y : integer;
begin
Result := TBitmap.Create;
Result.Width := OriginalBitmap.Width;
Result.Height := OriginalBitmap.Height;
for x := 0 to OriginalBitmap.Width-1 do
for y := 0 to OriginalBitmap.Height-1 do
begin
Result.Canvas.Pixels[x, y] := clBlack;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
var
imgf : TBitmap;
imgf2 : TBitmap;
begin
if od1.Execute then
begin
imgf := TBitmap.Create;
try
imgf.LoadFromFile(od1.FileName);
imgf2 := RGBBitmapTo1Bit(imgf);
try
imgf2.SaveToFile(ExtractFilePath(od1.FileName)+'test.bmp');
finally
imgf2.Free;
end;
finally
imgf.Free;
end;
end;
end;
Or this:
procedure RGBBitmapTo1Bit(OriginalBitmap : TBitmap);
var
x, y : integer;
begin
for x := 0 to OriginalBitmap.Width-1 do
for y := 0 to OriginalBitmap.Height-1 do
begin
OriginalBitmap.Canvas.Pixels[x, y] := clBlack;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
var
imgf : TBitmap;
begin
if od1.Execute then
begin
imgf := TBitmap.Create;
try
imgf.LoadFromFile(od1.FileName);
RGBBitmapTo1Bit(imgf);
imgf.SaveToFile(ExtractFilePath(od1.FileName)+'test.bmp');
finally
imgf.Free;
end;
end;
end;
That being said, RGBBitmapTo1Bit() is slow in both versions. A faster version would be more like this:
function RGBBitmapTo1Bit(OriginalBitmap : TBitmap) : TBitmap;
begin
Result := TBitmap.Create;
Result.Width := OriginalBitmap.Width;
Result.Height := OriginalBitmap.Height;
Result.Canvas.Brush.Color := clBlack;
Result.Canvas.FillRect(Rect(0, 0, Result.Width, Result.Height));
end;
function RGBBitmapTo1Bit(OriginalBitmap : TBitmap) : TBitmap;
begin
Result := TBitmap.Create;
Result.Canvas.Brush.Color := clBlack;
Result.Width := OriginalBitmap.Width;
Result.Height := OriginalBitmap.Height;
end;
Or:
procedure RGBBitmapTo1Bit(OriginalBitmap : TBitmap);
begin
OriginalBitmap.Canvas.Brush.Color := clBlack;
OriginalBitmap.Canvas.FillRect(Rect(0, 0, OriginalBitmap.Width, OriginalBitmap.Height));
end;
It also does not do what its name suggests - convert a bitmap to 1bit. To do that, you have to set the TBitmap.PixelFormat property instead:
function RGBBitmapTo1Bit(OriginalBitmap : TBitmap) : TBitmap;
begin
Result := TBitmap.Create;
Result.PixelFormat := pf1Bit;
Result.Canvas.Brush.Color := clBlack;
Result.Width := OriginalBitmap.Width;
Result.Height := OriginalBitmap.Height;
end;
Or:
procedure RGBBitmapTo1Bit(OriginalBitmap : TBitmap);
begin
OriginalBitmap.PixelFormat := pf1Bit;
OriginalBitmap.Canvas.Brush.Color := clBlack;
OriginalBitmap.Canvas.FillRect(Rect(0, 0, OriginalBitmap.Width, OriginalBitmap.Height));
end;
I want to Draw a Screenshot from the entire screen to a TForm1 Canvas.
This code works well in Delphi XE3
procedure TForm1.Button1Click(Sender: TObject);
var
c,scr: TCanvas;
r,r2: TRect;
begin
c := TCanvas.Create;
scr := TCanvas.Create;
c.Handle := GetWindowDC(GetDesktopWindow);
try
r := Rect(0, 0, 200, 200);
form1.Canvas.CopyRect(r, c, r);
finally
ReleaseDC(0, c.Handle);
c.Free;
end;
Now I want to copy the screenshot to another canvas first.
Is there a way to do this without getting this error?
procedure TForm1.Button1Click(Sender: TObject);
var
c,scr: TCanvas;
r,r2: TRect;
begin
c := TCanvas.Create;
scr := TCanvas.Create;
c.Handle := GetWindowDC(GetDesktopWindow);
try
r := Rect(0, 0, 200, 200);
scr.CopyRect(r,c,r); <-- Error, canvas does not allow drawing
form1.Canvas.CopyRect(r, scr, r); <-- Error, canvas does not allow drawing
finally
ReleaseDC(0, c.Handle);
c.Free;
end;
If you need to work with an additional canvas you will have to assign a HDC e.g.
var
WindowHandle:HWND;
ScreenCanvas,BufferCanvas: TCanvas;
r,r2: TRect;
ScreenDC,BufferDC :HDC;
BufferBitmap : HBITMAP;
begin
WindowHandle := 0;
ScreenCanvas := TCanvas.Create;
BufferCanvas := TCanvas.Create;
ScreenDC:=GetWindowDC(WindowHandle);
ScreenCanvas.Handle := ScreenDC;
BufferDC := CreateCompatibleDC(ScreenDC);
BufferCanvas.Handle := BufferDC;
BufferBitmap := CreateCompatibleBitmap(ScreenDC,
GetDeviceCaps(ScreenDC, HORZRES),
GetDeviceCaps(ScreenDC, VERTRES));
SelectObject(BufferDC, BufferBitmap);
try
r := Rect(0, 0, 200, 200);
BufferCanvas.CopyRect(r,ScreenCanvas,r);
form1.Canvas.CopyRect(r, BufferCanvas, r);
finally
ReleaseDC(WindowHandle, ScreenCanvas.Handle);
DeleteDC(BufferDC);
DeleteObject(BufferBitmap);
BufferCanvas.Free;
ScreenCanvas.Free;
end;
end;
It's a time to toss my solution into the pot!
procedure TForm1.FormClick(Sender: TObject);
var
ScreenCanvas: TCanvas;
begin
ScreenCanvas := TCanvas.Create;
try
ScreenCanvas.Handle := GetWindowDC(GetDesktopWindow);
Win32Check(ScreenCanvas.HandleAllocated);
Canvas.CopyRect(Canvas.ClipRect, ScreenCanvas, ScreenCanvas.ClipRect);
finally
ReleaseDC(GetDesktopWindow, ScreenCanvas.Handle);
ScreenCanvas.Free;
end;
end;
For full screenshots, I use this code:
form1.Hide;
sleep(500);
bmp := TBitmap.Create;
bmp.Height := Screen.Height;
bmp.Width := Screen.Width;
DCDesk := GetWindowDC(GetDesktopWindow);
BitBlt(bmp.Canvas.Handle, 0, 0, Screen.Width, Screen.Height, DCDesk, 0, 0, SRCCOPY);
form1.Show ;
FileName := 'Screenshot_'+FormatDateTime('mm-dd-yyyy-hhnnss',now());
bmp.SaveToFile(Format('C:\Screenshots\%s.bmp', [FileName]));
ReleaseDC(GetDesktopWindow, DCDesk);
bmp.Free;
How can I convert that to take a screenshot of only the active window.
First of all you have to get the right window. As sharptooth already noted you should use GetForegroundWindow instead of GetDesktopWindow. You have done it right in your improved version.
But then you have to resize your bitmap to the actual size of the DC/Window. You haven't done this yet.
And then make sure you don't capture some fullscreen window!
When I executed your code, my Delphi IDE was captured and as it is on fullscreen by default, it created the illusion of a fullscreen screenshot. (Even though your code is mostly correct)
Considering the above steps, I was successfully able to create a single-window screenshot with your code.
Just a hint: You can GetDC instead of GetWindowDC if you are only interested in the client area. (No window borders)
EDIT: Here's what I made with your code:
You should not use this code! Look at the improved version below.
procedure TForm1.Button1Click(Sender: TObject);
const
FullWindow = True; // Set to false if you only want the client area.
var
hWin: HWND;
dc: HDC;
bmp: TBitmap;
FileName: string;
r: TRect;
w: Integer;
h: Integer;
begin
form1.Hide;
sleep(500);
hWin := GetForegroundWindow;
if FullWindow then
begin
GetWindowRect(hWin,r);
dc := GetWindowDC(hWin) ;
end else
begin
Windows.GetClientRect(hWin, r);
dc := GetDC(hWin) ;
end;
w := r.Right - r.Left;
h := r.Bottom - r.Top;
bmp := TBitmap.Create;
bmp.Height := h;
bmp.Width := w;
BitBlt(bmp.Canvas.Handle, 0, 0, w, h, DC, 0, 0, SRCCOPY);
form1.Show ;
FileName := 'Screenshot_'+FormatDateTime('mm-dd-yyyy-hhnnss',now());
bmp.SaveToFile(Format('C:\Screenshots\%s.bmp', [FileName]));
ReleaseDC(hwin, DC);
bmp.Free;
end;
EDIT 2: As requested I'm adding a better version of the code, but I'm keeping the old one as a reference. You should seriously consider using this instead of your original code. It'll behave much nicer in case of errors. (Resources are cleaned up, your form will be visible again, ...)
procedure TForm1.Button1Click(Sender: TObject);
const
FullWindow = True; // Set to false if you only want the client area.
var
Win: HWND;
DC: HDC;
Bmp: TBitmap;
FileName: string;
WinRect: TRect;
Width: Integer;
Height: Integer;
begin
Form1.Hide;
try
Application.ProcessMessages; // Was Sleep(500);
Win := GetForegroundWindow;
if FullWindow then
begin
GetWindowRect(Win, WinRect);
DC := GetWindowDC(Win);
end else
begin
Windows.GetClientRect(Win, WinRect);
DC := GetDC(Win);
end;
try
Width := WinRect.Right - WinRect.Left;
Height := WinRect.Bottom - WinRect.Top;
Bmp := TBitmap.Create;
try
Bmp.Height := Height;
Bmp.Width := Width;
BitBlt(Bmp.Canvas.Handle, 0, 0, Width, Height, DC, 0, 0, SRCCOPY);
FileName := 'Screenshot_' +
FormatDateTime('mm-dd-yyyy-hhnnss', Now());
Bmp.SaveToFile(Format('C:\Screenshots\%s.bmp', [FileName]));
finally
Bmp.Free;
end;
finally
ReleaseDC(Win, DC);
end;
finally
Form1.Show;
end;
end;
Your code could be a lot simpler. When you have decided on which form you want to save, try the code I use:
procedure SaveFormBitmapToBMPFile( AForm : TCustomForm; AFileName : string = '' );
// Copies this form's bitmap to the specified file
var
Bitmap: TBitMap;
begin
Bitmap := AForm.GetFormImage;
try
Bitmap.SaveToFile( AFileName );
finally
Bitmap.Free;
end;
end;
This combines all the approaches described so far. It also handles multiple-monitor scenarios.
Pass in the kind of screenshot you want, and a TJpegImage, and it will assign your requested screenshot to that image.
///////////
uses
Jpeg;
type //define an ENUM to describe the possible screenshot types.
TScreenShotType = (sstActiveWindow, sstActiveClientArea,
sstPrimaryMonitor, sstDesktop);
///////////
procedure TfrmMain.GetScreenShot(shotType: TScreenShotType;
var img: TJpegImage);
var
w,h: integer;
DC: HDC;
hWin: Cardinal;
r: TRect;
tmpBmp: TBitmap;
begin
hWin := 0;
case shotType of
sstActiveWindow:
begin
//only the active window
hWin := GetForegroundWindow;
dc := GetWindowDC(hWin);
GetWindowRect(hWin,r);
w := r.Right - r.Left;
h := r.Bottom - r.Top;
end; //sstActiveWindow
sstActiveClientArea:
begin
//only the active client area (active window minus title bars)
hWin := GetForegroundWindow;
dc := GetDC(hWin);
GetWindowRect(hWin,r);
w := r.Right - r.Left;
h := r.Bottom - r.Top;
end; //sstActiveClientArea
sstPrimaryMonitor:
begin
//only the primary monitor. If 1 monitor, same as sstDesktop.
hWin := GetDesktopWindow;
dc := GetDC(hWin);
w := GetDeviceCaps(DC,HORZRES);
h := GetDeviceCaps(DC,VERTRES);
end; //sstPrimaryMonitor
sstDesktop:
begin
//ENTIRE desktop (all monitors)
dc := GetDC(GetDesktopWindow);
w := Screen.DesktopWidth;
h := Screen.DesktopHeight;
end; //sstDesktop
else begin
Exit;
end; //case else
end; //case
//convert to jpg
tmpBmp := TBitmap.Create;
try
tmpBmp.Width := w;
tmpBmp.Height := h;
BitBlt(tmpBmp.Canvas.Handle,0,0,tmpBmp.Width,
tmpBmp.Height,DC,0,0,SRCCOPY);
img.Assign(tmpBmp);
finally
ReleaseDC(hWin,DC);
FreeAndNil(tmpBmp);
end; //try-finally
end;
JCL comes to the rescue once again..
hwnd := GetForegroundWindow;
Windows.GetClientRect(hwnd, r);
JclGraphics.ScreenShot(theBitmap, 0, 0, r.Right - r.Left, r.Bottom - r.Top, hwnd);
// use theBitmap...
Thank you for this useful submission I thought I might make the code offered into a unit to use all over my application, here is the code I have running on DX10.2 Tokyo. Please note the example, watch out for memory leaks.
unit ScreenCapture;
interface
uses Windows, Vcl.Controls, Vcl.StdCtrls, VCL.Graphics,VCL.Imaging.JPEG, VCL.Forms;
function getScreenCapture( FullWindow: Boolean = True ) : TBitmap;
implementation
function getScreenCapture( FullWindow: Boolean ) : TBitmap;
var
Win: HWND;
DC: HDC;
WinRect: TRect;
Width: Integer;
Height: Integer;
begin
Result := TBitmap.Create;
//Application.ProcessMessages; // Was Sleep(500);
Win := GetForegroundWindow;
if FullWindow then
begin
GetWindowRect(Win, WinRect);
DC := GetWindowDC(Win);
end
else
begin
Windows.GetClientRect(Win, WinRect);
DC := GetDC(Win);
end;
try
Width := WinRect.Right - WinRect.Left;
Height := WinRect.Bottom - WinRect.Top;
Result.Height := Height;
Result.Width := Width;
BitBlt(Result.Canvas.Handle, 0, 0, Width, Height, DC, 0, 0, SRCCOPY);
finally
ReleaseDC(Win, DC);
end;
end;
end.
Example :
//Any event or button click, screenCapture is a TBitmap
screenCapture := getScreenCapture();
try
//Do some things with screen capture
Image1.Picture.Graphic := screenCapture;
finally
screenCapture.Free;
end;
Use GetForegroundWindow() instead of GetDesktopWindow().
You'll have to save the handle which GetForegroundWindow() return and pass the saved value into ReleaseDC() - to be sure that GetWindowDC() and ReleaseDC() are called exactly for the same window in case the active window changes between calls.
In case anyone is looking for a more cross-platform solution, this one claims Windows and MacOS-X support:
https://github.com/z505/screenshot-delphi
The shortest version of the Brian Frost code:
Screen.ActiveForm.GetFormImage.SaveToFile(Screen.ActiveForm.Caption+'.bmp');
Just one line of the code (Screenshot of the active window in the MDI application).