asked on

copy a part of a picture to a new file (.BMP or .JPG)

The source files (.BMP or .JPG) are the size 640 X 480 or bigger. I need to make the picture visible on screen. So far no problem. What I need is a peace of the picture copied into a new file (the size has to be 200 X 140).

The questions:
1) Is it possible to place a rectangle on top of the picture (200 X 140) so it can be moved by the mouse to the correct position in to the picture.
2) If question one is answered with yes. Is it possible to copy the part of the picture inside the rectangle to a new file (.BMP or .JPG).
3) Is it possible to reduce the colors from 24 bits to 8 bits (256 colors), otherwise the size of the file will be to big (.BMP) or is this by .JPG no problem. The size of the new file has to be arround 30 Kb maximum. How do I have to do that.

Is it possible to give a little example of the procedures and funtions needed to do this (to select the part of the picture, to save the part into a new file and to reduce the colors if nescesary).

Thanks in advance,
Dirk.

PS Sorry for my poor English.

Epsylon

1) Sorry, but that will take hours. I have no time for that.
2+3) Take a look at this code:

const x_size = 50;
y_size = 50;
x_offset = 100;
y_offset = 100;
var p: TPicture;
j: TJPEGImage;
b: TBitmap;
src, dest: TRect;
begin
src := Bounds(x_offset, y_offset, x_size, y_size);
dest := Bounds(0, 0, x_size, y_size);
p := TPicture.Create;
p.LoadFromFile('c:\my documents\pictures\kerstkaart.bmp');
b := TBitmap.Create;
b.Width := dest.Right - dest.Left + 1;
b.Height := dest.Bottom - dest.Top + 1;
b.Canvas.CopyRect(dest, p.Bitmap.Canvas, src);
j := TJPEGImage.Create;
j.Assign(b);
j.SaveToFile('image.jpg');
j.Free;
b.Free;
p.Free;
end;

Regards,

Epsylon.

ka1a

ASKER

Thanks Epsylon,

How can I get the prommised points to You?

Dirk.

ASKER CERTIFIED SOLUTION

kretzschmar

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

kretzschmar

oops eps, sorry, didn't see your comment ;-)

Epsylon

Never mind :o)

ka1a

ASKER

Meikl,

I just tried youre unit.

I can select a picture (.BMP or .JPG). Yhe picture becomes visible in image1.

There is a rectange visible. I can move it with the mouse.

But in image2 there becomes nothing visible. When push the save button an empty .BMP file is saved. There are no errormessages.

What am I doing wrong. I copied your text so I didn't make any type errors.

Any suggestions.

Thanks,
Dirk.

kretzschmar

hi dirk,

there is a checkbox, if the checkbox checked then the cutting is active by the mouseevent of the rectangle (PaintBox).

hope thats it ;-)

meikl

ka1a

ASKER

Meikl,

If the checkbox is checked or not, it makes no difference.

If you must find out what other reason it could be, please let me now.

Thanks,
Dirk.

PS Is it possible that I did make a mistake by constructing the Form? (A component on the wrong parrent or somthing like that?)

kretzschmar

hi ka1a,

here is the form as text, leave your email here, then i send you the little project

object Form1: TForm1
Left = 200
Top = 102
Width = 544
Height = 375
Caption = 'Form1'
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OnCreate = FormCreate
PixelsPerInch = 96
TextHeight = 13
object Splitter1: TSplitter
Left = 249
Top = 73
Width = 3
Height = 278
Cursor = crHSplit
end
object Panel1: TPanel
Left = 0
Top = 0
Width = 536
Height = 73
Align = alTop
Caption = 'Panel1'
TabOrder = 0
object CheckBox1: TCheckBox
Left = 336
Top = 8
Width = 97
Height = 17
Caption = 'CheckBox1'
TabOrder = 0
end
object Button1: TButton
Left = 24
Top = 8
Width = 75
Height = 25
Caption = 'Button1'
TabOrder = 1
OnClick = Button1Click
end
object Button2: TButton
Left = 112
Top = 8
Width = 75
Height = 25
Caption = 'Button2'
TabOrder = 2
OnClick = Button2Click
end
object Button3: TButton
Left = 304
Top = 40
Width = 75
Height = 25
Caption = 'Button3'
TabOrder = 3
OnClick = Button3Click
end
object Edit1: TEdit
Left = 392
Top = 24
Width = 121
Height = 21
TabOrder = 4
Text = 'Edit1'
end
object Edit2: TEdit
Left = 392
Top = 48
Width = 121
Height = 21
TabOrder = 5
Text = 'Edit2'
end
end
object ScrollBox1: TScrollBox
Left = 0
Top = 73
Width = 249
Height = 278
Align = alLeft
TabOrder = 1
object Image1: TImage
Left = 0
Top = 0
Width = 105
Height = 105
AutoSize = True
end
object PaintBox1: TPaintBox
Left = 120
Top = 32
Width = 105
Height = 105
OnMouseDown = PaintBox1MouseDown
OnMouseMove = PaintBox1MouseMove
OnMouseUp = PaintBox1MouseUp
OnPaint = PaintBox1Paint
end
end
object ScrollBox2: TScrollBox
Left = 252
Top = 73
Width = 284
Height = 278
Align = alClient
TabOrder = 2
object Image2: TImage
Left = 0
Top = 0
Width = 280
Height = 274
AutoSize = True
Center = True
end
end
object OpenPictureDialog1: TOpenPictureDialog
Filter = 'Bitmaps (*.bmp)|*.bmp|JPG (*.jpg)|*.jpg'
Left = 216
Top = 16
end
object SavePictureDialog1: TSavePictureDialog
Filter = 'Bitmaps (*.bmp)|*.bmp|JPeg (*.jpg)|*.jpg'
Left = 264
Top = 24
end
end

meikl

ka1a

ASKER

Meikl,

Please send the project to:

dirk.peeters@glo.be

Thanks,
Dirk.

PS: You realy save my day with this one, thanks again.

kretzschmar

is sent just now ;-)