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{
fpGUI - Free Pascal GUI Toolkit
Copyright (C) 2006 - 2010 See the file AUTHORS.txt, included in this
distribution, for details of the copyright.
See the file COPYING.modifiedLGPL, included in this distribution,
for details about redistributing fpGUI.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Description:
This unit implements color selectors using a ColorWheel and
a ValueBar. Color results are in HSV or TfpgColor format.
}
unit fpg_ColorWheel;
{$mode objfpc}{$H+}
interface
uses
Classes, fpg_base, fpg_main, fpg_widget;
type
// forward declaration
TfpgValueBar = class;
TfpgColorWheel = class(TfpgWidget)
protected
FValueBar: TfpgValueBar;
FHue: longint;
FSaturation: double;
FMarginWidth: longint;
FCursorSize: longint;
FWhiteAreaPercent: longint; // 0 to 50 percent of circle radius that is pure white
FOnChange: TNotifyEvent;
FImage: TfpgImage; // cached colorwheel image
FRecalcWheel: Boolean; // should chached FImage be recalculated
procedure HSFromPoint(X, Y: longint; out H: longint; out S: double);
procedure DrawCursor;
procedure SetMarginWidth(NewWidth: longint);
procedure SetCursorSize(NewSize: longint);
procedure SetValueBar(AValueBar: TfpgValueBar);
procedure SetWhiteAreaPercent(WhiteAreaPercent: longint);
procedure SetBackgroundColor(const AValue: TfpgColor); override;
procedure Notification(AComponent: TComponent; Operation: TOperation); override;
function DrawWidth: longint;
function DrawHeight: longint;
procedure Change;
procedure HandlePaint; override;
procedure HandleLMouseDown(x, y: integer; shiftstate: TShiftState); override;
procedure HandleMouseMove(x, y: integer; btnstate: word; shiftstate: TShiftState); override;
procedure HandleLMouseUp(x, y: integer; shiftstate: TShiftState); override;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
property Hue: longint Read FHue;
property Saturation: double Read FSaturation;
procedure SetSelectedColor(const NewColor: TfpgColor);
published
property BackgroundColor;
property ValueBar: TfpgValueBar Read FValueBar Write SetValueBar;
property MarginWidth: longint Read FMarginWidth Write SetMarginWidth default 5;
property CursorSize: longint Read FCursorSize Write SetCursorSize default 5;
property WhiteAreaPercent: longint Read FWhiteAreaPercent Write SetWhiteAreaPercent default 10;
property OnChange: TNotifyEvent Read FOnChange Write FOnChange;
end;
TfpgValueBar = class(TfpgWidget)
protected
FColorWheel: TfpgColorWheel;
FHue: longint;
FSaturation: double;
FValue: double;
FMarginWidth: longint;
FCursorHeight: longint;
FOnChange: TNotifyEvent;
procedure DrawCursor;
procedure SetMarginWidth(NewWidth: longint);
procedure SetValue(Value: double);
procedure SetCursorHeight(CursorHeight: longint);
function GetSelectedColor: TfpgColor;
procedure Change;
function DrawWidth: longint;
function DrawHeight: longint;
function ValueFromY(Y: longint): real;
procedure DrawLine(Y: longint);
procedure HandlePaint; override;
procedure HandleLMouseDown(x, y: integer; shiftstate: TShiftState); override;
procedure HandleMouseMove(x, y: integer; btnstate: word; shiftstate: TShiftState); override;
procedure HandleLMouseUp(x, y: integer; shiftstate: TShiftState); override;
public
constructor Create(AOwner: TComponent); override;
procedure SetHS(Hue: longint; Sat: double);
published
property BackgroundColor;
property Value: double Read FValue Write SetValue;
property SelectedColor: TfpgColor Read GetSelectedColor;
property MarginWidth: longint Read FMarginWidth Write SetMarginWidth;
property CursorHeight: longint Read FCursorHeight Write SetCursorHeight;
property OnChange: TNotifyEvent Read FOnChange Write FOnChange;
end;
implementation
uses
fpg_ColorMapping;
const
RadToHue: double = 1536 / (2 * pi);
function AngleFrom(x, y: double): double;
// Quadrants are laid out as follows:
//
// 1|0
// ---+----
// 2|3
begin
if X = 0 then
begin
if Y > 0 then
Result := pi / 2
else
Result := 3 * pi / 2;
end
else
begin
Result := arctan(abs(y) / abs(x));
if (x < 0) and (y >= 0) then
// quadrant 1
Result := pi - Result
else if (x < 0) and (y < 0) then
// quadrant 2
Result := Result + pi
else if (x >= 0) and (y < 0) then
// quadrant 3
Result := 2 * pi - Result;
end;
end;
{ TfpgColorWheel }
function TfpgColorWheel.DrawWidth: longint;
begin
Result := Width - FMarginWidth * 2;
end;
function TfpgColorWheel.DrawHeight: longint;
begin
Result := Height - FMarginWidth * 2;
end;
procedure TfpgColorWheel.SetSelectedColor(const NewColor: TfpgColor);
var
Value: double;
begin
RGBToHSV(NewColor, FHue, FSaturation, Value);
Change;
if FValueBar <> nil then
FValueBar.Value := Value;
end;
procedure TfpgColorWheel.Change;
begin
if FValueBar <> nil then
FValueBar.SetHS(FHue, FSaturation);
if FOnChange <> nil then
FOnChange(self);
Invalidate;
end;
procedure TfpgColorWheel.HandlePaint;
var
x, y: longint;
lHue: longint;
lsaturation: double;
c: TfpgColor;
begin
// clear background rectangle
Canvas.Clear(BackgroundColor);
// margins too big
if (Width < MarginWidth * 2) or (Height < MarginWidth * 2) then
Exit; //==>
if csDesigning in ComponentState then
begin
// When designing, don't draw colors
// but draw an outline
Canvas.SetLineStyle(1, lsDash);
Canvas.DrawRectangle(GetClientRect);
Canvas.SetLineStyle(1, lsSolid);
Canvas.Color := clUIDesignerGreen;
Canvas.FillArc(FMarginWidth, FMarginWidth, DrawWidth, DrawHeight, 0, 360);
Canvas.Color := clHilite1;
Canvas.DrawArc(FMarginWidth, FMarginWidth, DrawWidth, DrawHeight, 45, 180);
Canvas.Color := clShadow1;
Canvas.DrawArc(FMarginWidth, FMarginWidth, DrawWidth, DrawHeight, 225, 180);
Canvas.TextColor := clShadow1;
Canvas.DrawText(5, 5, Name + ': ' + ClassName);
DrawCursor;
Exit; //==>
end;
if (FImage = nil) or FRecalcWheel then
begin
// we must only do this when needed, because it's very slow
if FImage <> nil then
FImage.Free;
FImage := TfpgImage.Create;
FImage.AllocateImage(32, DrawWidth, DrawHeight);
for X := 0 to DrawWidth - 1 do
begin
for Y := 0 to DrawHeight - 1 do
begin
// work out hue and saturation for point
HSFromPoint(X, Y, lHue, lSaturation);
if lSaturation <= 1.0 then
begin
// point is within wheel
C := HSVToRGB(lHue, lSaturation, 1.0);
// draw the pixel
Canvas.Pixels[X + FMarginWidth, Y + FMarginWidth] := C;
FImage.Colors[x, y] := c;
end
else
// point is outside wheel. Also incase color is alias, lookup the RGB values.
FImage.Colors[x, y] := fpgColorToRGB(BackgroundColor);
end;
FImage.UpdateImage;
end;
FRecalcWheel := False;
end
else
begin
// paint buffer image seeing that we have it
Canvas.DrawImage(FMarginWidth, FMarginWidth, FImage);
end;
DrawCursor;
end;
procedure TfpgColorWheel.HandleLMouseDown(x, y: integer; shiftstate: TShiftState);
begin
inherited HandleLMouseDown(x, y, shiftstate);
Dec(X, FMarginWidth);
Dec(Y, FMarginWidth);
HSFromPoint(X, Y, FHue, FSaturation);
if FSaturation > 1.0 then
FSaturation := 1.0;
Change;
CaptureMouse;
end;
procedure TfpgColorWheel.HandleMouseMove(x, y: integer; btnstate: word;
shiftstate: TShiftState);
begin
inherited HandleMouseMove(x, y, btnstate, shiftstate);
// is mouse still captured (LButton down)?
if ((btnstate and MOUSE_LEFT) = 0) then
Exit; //==>
Dec(X, FMarginWidth);
Dec(Y, FMarginWidth);
HSFromPoint(X, Y, FHue, FSaturation);
if FSaturation > 1.0 then
FSaturation := 1.0;
Change;
end;
procedure TfpgColorWheel.HandleLMouseUp(x, y: integer; shiftstate: TShiftState);
begin
inherited HandleLMouseUp(x, y, shiftstate);
ReleaseMouse;
end;
constructor TfpgColorWheel.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FMarginWidth := 5;
FCursorSize := 5;
Width := 100;
Height := 100;
Name := 'ColorWheel';
FWhiteAreaPercent := 10;
FRecalcWheel := True;
end;
destructor TfpgColorWheel.Destroy;
begin
if FImage <> nil then
FImage.Free;
inherited Destroy;
end;
// Calculate hue and saturation for a given point in the color wheel
procedure TfpgColorWheel.HSFromPoint(X, Y: longint; out H: longint; out S: double);
var
xp, yp: double;
halfw, halfh: longint;
begin
halfw := DrawWidth div 2;
halfh := DrawHeight div 2;
xp := (x - halfw) / halfw; // x as -1..1
yp := (y - halfh) / halfh; // y as -1..1
H := Trunc(RadToHue * AngleFrom(xp, -yp));
S := sqrt(xp * xp + yp * yp);
// scale saturation and limit to white, for white area
S := S * (1 + (FWhiteAreaPercent / 100.0)) - (FWhiteAreaPercent / 100.0);
if S < 0 then
S := 0;
end;
procedure TfpgColorWheel.DrawCursor;
var
Angle: Double;
X, Y: longint;
S: Double;
a: Double;
len: longint;
begin
Angle := FHue/RadToHue;
// Scale distance from centre for white area
S := FSaturation;
if S > 0 then
begin
a := FWhiteAreaPercent / 100.0;
S := (S * (1 - a)) + a;
end;
// work out point for selected hue and saturation
X := Trunc(Width div 2+cos(Angle) * S * (DrawWidth div 2));
Y := Trunc(Height div 2+sin(Angle) * S * -(DrawHeight div 2));
// draw a crosshair with centre at mouse cursor position
len := FCursorSize*2 + 2; // length of crosshair lines
Canvas.XORFillRectangle($FFFFFF, X-FCursorSize, Y, len, 2);
Canvas.XORFillRectangle($FFFFFF, X, Y-FCursorSize, 2, len);
end;
procedure TfpgColorWheel.SetMarginWidth(NewWidth: longint);
begin
FMarginWidth := NewWidth;
if WinHandle = 0 then
Exit; //==>
Invalidate;
end;
procedure TfpgColorWheel.SetCursorSize(NewSize: longint);
begin
FCursorSize := NewSize;
if WinHandle = 0 then
Exit; //==>
Invalidate;
end;
procedure TfpgColorWheel.SetValueBar(AValueBar: TfpgValueBar);
begin
if FValueBar <> nil then
// tell the old value bar it's no longer controlled by this wheel
FValueBar.FColorWheel := nil;
FValueBar := AValueBar;
if FValueBar <> nil then
begin
// Tell value bar it is controlled by this component
FValueBar.FColorWheel := Self;
// request notification when other is freed
FValueBar.FreeNotification(Self);
end;
end;
procedure TfpgColorWheel.SetWhiteAreaPercent(WhiteAreaPercent: longint);
begin
if WhiteAreaPercent > 50 then
WhiteAreaPercent := 50;
if WhiteAreaPercent < 0 then
WhiteAreaPercent := 0;
FWhiteAreaPercent := WhiteAreaPercent;
Invalidate;
end;
procedure TfpgColorWheel.SetBackgroundColor(const AValue: TfpgColor);
begin
FRecalcWheel := True;
inherited SetBackgroundColor(AValue);
end;
procedure TfpgColorWheel.Notification(AComponent: TComponent; Operation: TOperation);
begin
inherited Notification(AComponent, Operation);
if Operation = opRemove then
begin
if AComponent = FValueBar then
FValueBar := nil;
end;
end;
{ TfpgValueBar }
procedure TfpgValueBar.DrawLine(Y: longint);
var
DrawVal: double;
c: TfpgColor;
begin
DrawVal := ValueFromY(Y);
C := HSVToRGB(FHue, FSaturation, DrawVal);
Canvas.Color := c;
Canvas.DrawLine(FMarginWidth, Y, Width - FMarginWidth - 1, Y);
end;
procedure TfpgValueBar.HandlePaint;
var
y: longint;
r: TfpgRect;
begin
// inherited HandlePaint;
Canvas.Clear(BackgroundColor);
if csDesigning in ComponentState then
begin
// when designing just draw
// a rectangle to indicate
Canvas.Color := clBlack;
Canvas.SetLineStyle(1, lsDash);
Canvas.DrawRectangle(GetClientRect);
if (Width < MarginWidth * 2) or (Height < MarginWidth * 2) then
Exit; //==>
r := GetClientRect;
InflateRect(r, -FMarginWidth, -FMarginWidth);
Canvas.Color := clShadow1;
Canvas.SetLineStyle(1, lsSolid);
Canvas.DrawRectangle(r);
Canvas.TextColor := clShadow1;
Canvas.DrawText(5, 5, Width, Height, Name + ': ' + ClassName, TextFlagsDflt + [txtWrap]);
DrawCursor;
exit;
end;
// Draw margins
r.left := 0;
r.setbottom(0);
r.setright(FMarginWidth - 1);
r.top := Height - 1;
Canvas.Color := BackgroundColor;
Canvas.FillRectangle(r); // left
r.left := Width - FMarginWidth;
r.setright(Width - 1);
Canvas.FillRectangle(r); // right
r.left := FMarginWidth;
r.setright(Width - FMarginWidth - 1);
r.setbottom(Height - FMarginWidth);
r.top := Height - 1;
Canvas.FillRectangle(r); // top
r.setbottom(0);
r.top := FMarginWidth - 1;
Canvas.FillRectangle(r); // bottom
if (Width < MarginWidth * 2) or (Height < MarginWidth * 2) then
Exit; //==>
for Y := 0 to DrawHeight - 1 do
DrawLine(Y + FMarginWidth);
DrawCursor;
end;
procedure TfpgValueBar.HandleLMouseDown(x, y: integer; shiftstate: TShiftState);
begin
inherited HandleLMouseDown(x, y, shiftstate);
FValue := ValueFromY(Y);
Change;
CaptureMouse;
end;
procedure TfpgValueBar.HandleMouseMove(x, y: integer; btnstate: word;
shiftstate: TShiftState);
begin
inherited HandleMouseMove(x, y, btnstate, shiftstate);
if ((btnstate and MOUSE_LEFT) = 0) then
Exit; //==>
FValue := ValueFromY(Y);
Change;
end;
procedure TfpgValueBar.HandleLMouseUp(x, y: integer; shiftstate: TShiftState);
begin
inherited HandleLMouseUp(x, y, shiftstate);
ReleaseMouse;
end;
constructor TfpgValueBar.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FMarginWidth := 5;
FValue := 1.0;
Width := 100;
Height := 100;
Name := 'ValueBar';
FCursorHeight := 10;
end;
procedure TfpgValueBar.SetHS(Hue: longint; Sat: double);
begin
FHue := Hue;
FSaturation := Sat;
Invalidate;
Change;
end;
procedure TfpgValueBar.SetValue(Value: double);
begin
FValue := Value;
Change;
end;
function TfpgValueBar.DrawWidth: longint;
begin
Result := Width - FMarginWidth * 2;
end;
function TfpgValueBar.DrawHeight: longint;
begin
Result := Height - FMarginWidth * 2;
end;
procedure TfpgValueBar.DrawCursor;
var
Y: longint;
r: TfpgRect;
begin
if (Width < MarginWidth * 2) or
(Height < MarginWidth * 2) then
Exit; //==>
Y := Trunc((FValue * DrawHeight) + FMarginWidth);
r.SetRect(FMarginWidth-1, Y - (FCursorHeight div 2), DrawWidth+1, FCursorHeight);
Canvas.Color := GetSelectedColor;
Canvas.FillRectangle(r);
Canvas.Color := clBlack;
Canvas.DrawControlFrame(r);
end;
procedure TfpgValueBar.SetMarginWidth(NewWidth: longint);
begin
if MarginWidth < 0 then
MarginWidth := 0;
FMarginWidth := NewWidth;
Invalidate;
end;
procedure TfpgValueBar.SetCursorHeight(CursorHeight: longint);
begin
if CursorHeight < 3 then
CursorHeight := 3;
FCursorHeight := CursorHeight;
Invalidate;
end;
function TfpgValueBar.GetSelectedColor: TfpgColor;
begin
Result := HSVToRGB(FHue, FSaturation, FValue);
end;
function TfpgValueBar.ValueFromY(Y: longint): real;
begin
Result := (Y - MarginWidth) / (DrawHeight - 1);
if Result < 0 then
Result := 0;
if Result > 1.0 then
Result := 1.0;
end;
procedure TfpgValueBar.Change;
begin
Invalidate;
if FOnChange <> nil then
FOnChange(self);
end;
end.
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