Double Gradient

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Unit

With this unit 'ngradient' you can easily make gradients for toolbars, buttons, etc. Save the below code in a text file 'ngradient.pas' and add 'ngradient' in the 'uses' section of your project.

<delphi>unit ngradient;

{$mode objfpc}{$H+}

interface

uses

 Classes, Graphics;

type

 TnGradientInfo = record
   StartColor,StopColor:TColor;
   Direction: TGradientDirection;
   endPercent:single; // This is not the percent of the width, this is the percent of the end ob the rect- which means, if this value is 1 - the rect could be from 0.99 to 1 and need not be from 0 to 1
 end;

function DoubleGradientFill(ARect: TRect; AStart1,AStop1,AStart2,AStop2: TColor;

 ADirection1,ADirection2,APos: TGradientDirection; AValue: Single): TBitmap;

function nGradientFill(ARect: TRect;APos: TGradientDirection; AGrandient: array of TnGradientInfo): TBitmap;

implementation

function nGradientFill(ARect: TRect;APos: TGradientDirection; AGrandient: array of TnGradientInfo): TBitmap; var

 i:integer;
 AnRect,OldRect: TRect;

begin

 Result := TBitmap.Create;
 Result.Width:=ARect.Right-ARect.Left;
 Result.Height:=ARect.Bottom-ARect.Top;
 OldRect := ARect;
 if APos = gdVertical then OldRect.Bottom := ARect.Top
    else OldRect.Right := ARect.Left ;   // upside down...  in case of i = 0...

 for i := 0 to high(AGrandient) do
     begin
     AnRect:=OldRect;
     if APos = gdVertical then
        begin
        AnRect.Bottom:=Round((ARect.Bottom-ARect.Top) * AGrandient[i].endPercent + ARect.Top);
        AnRect.Top:=OldRect.Bottom;
        end
       else
        begin
        AnRect.Right:=Round((ARect.Right-ARect.Left) * AGrandient[i].endPercent + ARect.Left);
        AnRect.Left:=OldRect.Right;
        end;

     Result.Canvas.GradientFill(AnRect,AGrandient[i].StartColor,AGrandient[i].StopColor,AGrandient[i].Direction);
     OldRect := AnRect;
     end;

end;

function DoubleGradientFill(ARect: TRect; AStart1,AStop1,AStart2,AStop2: TColor;

 ADirection1,ADirection2,APos: TGradientDirection; AValue: Single): TBitmap;

var

 ABitmap: TBitmap; ARect1,ARect2: TRect;

begin

 ABitmap := TBitmap.Create;
 ABitmap.Width:=ARect.Right;
 ABitmap.Height:=ARect.Bottom;
 if AValue <> 0 then begin
   ARect1:=ARect;
 end;
 if AValue <> 1 then begin
   ARect2:=ARect;
 end;
 if APos = gdVertical then begin
   ARect1.Bottom:=Round(ARect1.Bottom * AValue);
   ARect2.Top:=ARect1.Bottom;
 end
 else if APos = gdHorizontal then begin
   ARect1.Right:=Round(ARect1.Right * AValue);
   ARect2.Left:=ARect1.Right;
 end;
 if AValue <> 0 then begin
   ABitmap.Canvas.GradientFill(ARect1,AStart1,AStop1,ADirection1);
 end;
 if AValue <> 1 then begin
   ABitmap.Canvas.GradientFill(ARect2,AStart2,AStop2,ADirection2);
 end;
 Result:=ABitmap;

end;

end.</delphi>

Usage

First you must have a 'TBitmap' to store the gradient, then you can draw the image, for example, in all the 'Form1' visible area:

This is the result (using DoubleGradientFill).

<delphi>procedure TForm1.FormPaint(Sender: TObject); var

 ABitmap: TBitmap;

begin

 ABitmap:=DoubleGradientFill(Self.ClientRect,clMedGray,clWhite,clSilver,clGray,gdVertical,gdVertical,gdVertical,0.50);
 Self.Canvas.Draw(0,0,ABitmap);
 ABitmap.Free

end;</delphi>

Editor

nGradient Editor is an updated version of Double Gradient Editor with a lot of changes and improvements, like the ability to create gradients with 'n' number of gradients.

nGradient Editor

With nGradient Editor you can use 'n' (number) of gradients.

Version 1.1

• Name to n Gradient Edit, just because it is not any more double...
• I doesn't realy understand how to save configs - please corret it. Thanks
• I comment the Copy-to-clipboard thing - to lazy to corret it...
• i stopped the dpi thing because the editor doesn't look ok on my pc, remove "//" in Form.Create if you want to use it.
• I changed the editor for arrays, i use a stringlist. Double Click on StartColor /StopColor or Gradient for an Combobox / ColorDialog.
• I paint on an Image.
• The Image is not longer in the middle - i Had some problems, if you could fix it : great.
• You can scale the Form.
• I tried to seperate render and the rest...

Bugfixes: <delphi>(Rect.Bottom) *37 //and i corrected them to (Rect.Bottom - Rect.Top) * 37 + Rect.Top. //If Top and left was 0 there was no problem ...</delphi>

<delphi>//Also i just changed the line GradientPB.Canvas.Draw(0,0,ABitmap); //to Panel1.Canvas.Draw(0,0,ABitmap);</delphi>

Double Gradient Editor

Also you can use the 'Double Gradient Editor' that is a GUI to instantly see the result (only for double gradients), save to a bitmap file, save to '*.doublegradient' session file or just copy code to clipboard to use in lazarus.

• To access the menu right click the ScrollBox (gradient area):
  • Save bitmap.. Show a dialog to save as a *.bmp file.
  • Load gradient.. Show a dialog to load a *.doublegradient session file.
  • Save gradient.. Show a dialog to save the current session settings to a file.
  • Copy code to clipboard.. Just copy the settings as text in the clipboard, then you can use it to paste in lazarus source editor to call the doublegradientfill procedure.

• default.doublegradient: this file has the last settings in the editor, is loaded at startup, saved when you close the application.

Downloads

nGradient Editor 1.1 Source Code ngdedit1.1.zip (26.14 KB)

Double Gradient Editor 1.0 Source Code dbgdedit1.0.zip (5.64 KB)

You are free to edit and improve this editor, this is free of charge.

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