summaryrefslogtreecommitdiff
path: root/src/gui/fpg_colorwheel.pas
blob: ed90dc7931b3e7cfcc49b618988e810647989f77 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
{
    fpGUI  -  Free Pascal GUI Library

    Copyright (C) 2006 - 2009 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 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.Color := clHilite1;
    Canvas.DrawArc(Width div 2, Height div 2, DrawWidth div 2 + 1,
        DrawHeight div 2 + 1, 45, 180);
    Canvas.Color := clShadow1;
    Canvas.DrawArc(Width div 2, Height div 2, DrawWidth div 2 + 1,
        DrawHeight div 2 + 1, 225, 180);
    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);
    FImage.UpdateImage;
    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;
    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.SetLineStyle(1, lsDash);
    Canvas.DrawRectangle(GetClientRect);
    if (Width < MarginWidth * 2) or (Height < MarginWidth * 2) then
      Exit;  //==>
    r := GetClientRect;
    InflateRect(r, FMarginWidth, FMarginWidth);
    Canvas.DrawRectangle(r);
    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.