Mega Code Archive
Converting text to gif images
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Title: Converting text to gif images
Question: Sometimes, it is necessary to convert text to Gif images, to put in web pages. This article shows how to convert text to Gif images, developing a component to do it
Answer:
To convert some text to an image of any kind, the only thing to do is to create this image and draw the text on its canvas. This code converts a text in a memo to a 100 x 100 bitmap:
var
Bitmap : TBitmap;
begin
Bitmap := TBitmap.Create;
try
Bitmap.Width := 100;
Bitmap.Height := 100;
Bitmap.Canvas.TextOut(0,0,Memo1.Text);
Bitmap.SaveToFile('text.bmp');
finally
Bitmap.Free;
end;
end;
This code doesn't handle wordwraps. The easiest way to handle text wordwrap in custom widths is using Windows API DrawText function. Its last parameter is a Flags parameter, where you can specify DT_WORDBREAK to handle word breaks. You must supply a rectangle and it will break the text to fit. These lines show how to do it:
R := Rect(0,0,Bitmap.Width,Bitmap.Height);
DrawText(Handle,PChar(Memo1.Text),-1,R,DT_NOPREFIX or DT_WORDBREAK);
Delphi doesn't support Gif images by default. To convert the text to a Gif image, you must download Anders Melander's TGifImage component (http://www.melander.dk/delphi/gifimage). Then, you can use TGifImage to create a Gif image from the text:
var
Gif : TGifImage;
R : TRect;
Bitmap : TBitmap;
begin
// creates a bitmap to draw the text
Bitmap := TBitmap.Create;
try
Bitmap.Width := 100;
Bitmap.Height := 100;
Gif := TGifImage.Create;
try
Gif.Width := 100;
Gif.Height := 100;
// draw the text in the bitmap canvas
with Bitmap.Canvas do begin
R := Rect(0,0,Bitmap.Width,Bitmap.Height);
DrawText(Handle,PChar(Memo1.Text),-1,R,DT_NOPREFIX or DT_WORDBREAK);
end;
// assign the bitmap to the gif image
Gif.Assign(Bitmap);
// create the gif file
Gif.SaveToFile('test.gif');
finally
Gif.Free;
end;
finally
Bitmap.Free;
end;
With this information, we can now create a new component, TText2Gif, that converts some text to a Gif image. This component has three properties, Width, Height and Font, to select the image Width and Height and the font of the drawn text. It has one method, CreateGifFile(aText, aFullPath: string), which takes a text and creates a Gif image. The full code of the component is this:
unit Txt2Gif;
interface
uses
Windows, SysUtils, Classes, GifImage, Graphics, Types;
type
TTxt2Gif = class(TComponent)
private
FHeight: Integer;
FWidth: Integer;
FFont: TFont;
procedure SetFont(const Value: TFont);
procedure SetHeight(const Value: Integer);
procedure SetWidth(const Value: Integer);
{ Private declarations }
protected
{ Protected declarations }
public
{ Public declarations }
constructor Create(AOwner : TComponent); override;
destructor Destroy; override;
procedure CreateGifFile(aText, aFullPath: string);
published
{ Published declarations }
property Width : Integer read FWidth write SetWidth default 100;
property Height : Integer read FHeight write SetHeight default 100;
property Font : TFont read FFont write SetFont;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('BSComps', [TTxt2Gif]);
end;
{ TTxt2Gif }
constructor TTxt2Gif.Create(AOwner: TComponent);
begin
inherited;
FWidth := 100;
FHeight := 100;
FFont := TFont.Create;
end;
procedure TTxt2Gif.CreateGifFile(aText, aFullPath: string);
var
Gif : TGifImage;
R : TRect;
Bitmap : TBitmap;
begin
// create the bitmap to draw the text
Bitmap := TBitmap.Create;
try
Bitmap.Width := FWidth;
Bitmap.Height := FHeight;
Gif := TGifImage.Create;
try
Gif.Width := FWidth;
Gif.Height := FHeight;
// draw the text
with Bitmap.Canvas do begin
Font.Assign(FFont);
R := Rect(0,0,FWidth,FHeight);
DrawText(Handle,PChar(aText),-1,R,DT_NOPREFIX or DT_WORDBREAK);
end;
// assign the bitmap to the gif image
Gif.Assign(Bitmap);
// save the image to a file
Gif.SaveToFile(aFullPath);
finally
Gif.Free;
end;
finally
Bitmap.Free;
end;
end;
destructor TTxt2Gif.Destroy;
begin
FFont.Free;
inherited;
end;
procedure TTxt2Gif.SetFont(const Value: TFont);
begin
FFont := Value;
end;
procedure TTxt2Gif.SetHeight(const Value: Integer);
begin
FHeight := Value;
end;
procedure TTxt2Gif.SetWidth(const Value: Integer);
begin
FWidth := Value;
end;
end.
To use this component, you only have to install it in the palette, drop one in our Form. set the width, height and font and use some code like this:
Txt2Gif1.CreateGifFile(Memo1.Text,'test.gif');
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