1 | UNIT Gradient;
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2 |
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3 | INTERFACE
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4 |
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5 | USES Classes, Forms, Graphics;
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6 |
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7 | TYPE
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8 | TDirection = (dLeft, dRight, dUp, dDown);
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9 |
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10 | TGradient = CLASS(TControl)
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11 | PRIVATE
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12 | FDirection : TDirection;
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13 | FStartColor : TColor;
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14 | FEndColor : TColor;
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15 | PROCEDURE SetDirection(NewDirection:TDirection);
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16 | PROCEDURE SetStartColor(NewColor:TColor);
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17 | PROCEDURE SetEndColor(NewColor:TColor);
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18 | PROPERTY Caption;
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19 | PROPERTY Font;
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20 | PROPERTY Color;
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21 | PROPERTY PenColor;
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22 | PROPERTY ParentColor;
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23 | PROPERTY ParentPenColor;
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24 | PROPERTY TabStop;
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25 | PROTECTED
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26 | PROCEDURE SetupComponent; OVERRIDE;
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27 | PUBLIC
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28 | PROCEDURE Redraw(CONST rc:TRect); OVERRIDE;
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29 | PUBLISHED
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30 | PROPERTY Align;
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31 | PROPERTY DragCursor;
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32 | PROPERTY DragMode;
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33 | PROPERTY Enabled;
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34 | PROPERTY ParentFont;
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35 | PROPERTY ParentShowHint;
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36 | PROPERTY PopupMenu;
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37 | PROPERTY ShowHint;
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38 | PROPERTY TabOrder;
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39 | PROPERTY Visible;
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40 | PROPERTY ZOrder;
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41 |
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42 | PROPERTY OnCanDrag;
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43 | PROPERTY OnCommand;
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44 | PROPERTY OnDblClick;
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45 | PROPERTY OnDragDrop;
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46 | PROPERTY OnDragOver;
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47 | PROPERTY OnEndDrag;
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48 | PROPERTY OnEnter;
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49 | PROPERTY OnExit;
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50 | PROPERTY OnFontChange;
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51 | PROPERTY OnMouseClick;
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52 | PROPERTY OnMouseDblClick;
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53 | PROPERTY OnMouseDown;
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54 | PROPERTY OnMouseMove;
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55 | PROPERTY OnMouseUp;
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56 | PROPERTY OnResize;
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57 | PROPERTY OnSetupShow;
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58 | PROPERTY OnStartDrag;
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59 | PROPERTY Direction:TDirection read FDirection write SetDirection;
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60 | PROPERTY StartColor:TColor read FStartColor write SetStartColor;
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61 | PROPERTY EndColor:TColor read FEndColor write SetEndColor;
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62 | END;
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63 |
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64 | IMPLEMENTATION
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65 |
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66 | PROCEDURE TGradient.SetDirection(NewDirection:TDirection);
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67 | BEGIN
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68 | FDirection:=NewDirection;
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69 | Invalidate;
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70 | END;
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71 |
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72 | PROCEDURE TGradient.SetStartColor(NewColor:TColor);
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73 | BEGIN
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74 | FStartColor:=NewColor;
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75 | Invalidate;
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76 | END;
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77 |
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78 | PROCEDURE TGradient.SetEndColor(NewColor:TColor);
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79 | BEGIN
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80 | FEndColor:=NewColor;
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81 | Invalidate;
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82 | END;
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83 |
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84 | PROCEDURE TGradient.SetupComponent;
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85 | BEGIN
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86 | Inherited SetUpComponent;
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87 | Name:= 'Gradient';
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88 | FDirection:= dUp;
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89 | FStartColor:=clBlack;
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90 | FEndColor:=clBlue;
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91 | Width:=200;
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92 | Height:=200;
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93 | ZOrder:=zoBottom;
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94 | TabStop:=FALSE;
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95 | END;
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96 |
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97 | PROCEDURE TGradient.Redraw(CONST rc:TRect);
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98 | VAR
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99 | SaveColor:TColor;
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100 | DRed,DGreen,DBlue,DR,DG,DB:Extended;
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101 | StartLoop,EndLoop:LONGINT;
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102 | rec:TRect;
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103 | BEGIN
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104 | SaveColor:=Canvas.Pen.Color;
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105 | Canvas.ClipRect:=rc;
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106 |
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107 | DRed:=TRGB(FStartColor).Red;
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108 | DGreen:=TRGB(FStartColor).Green;
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109 | DBlue:=TRGB(FStartColor).Blue;
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110 | DR:=TRGB(FEndColor).Red-DRed;
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111 | DG:=TRGB(FEndColor).Green-DGreen;
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112 | DB:=TRGB(FEndColor).Blue-DBlue;
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113 |
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114 | CASE FDirection OF
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115 | dUp,dDown,dLeft,dRight:
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116 | BEGIN
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117 | IF FDirection IN [dUp,dDown] THEN
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118 | BEGIN
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119 | DR:=DR / Height;
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120 | DG:=DG / Height;
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121 | DB:=DB / Height;
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122 | END
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123 | ELSE
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124 | BEGIN
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125 | DR:=DR / Width;
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126 | DG:=DG / Width;
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127 | DB:=DB / Width;
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128 | END;
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129 |
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130 | IF FDirection=dUp THEN
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131 | BEGIN
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132 | StartLoop:=0;
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133 | EndLoop:=Height+1;
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134 | END
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135 | ELSE IF FDirection=dDown THEN
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136 | BEGIN
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137 | StartLoop:=Height+1;
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138 | EndLoop:=0;
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139 | END
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140 | ELSE IF FDirection=dLeft THEN
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141 | BEGIN
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142 | StartLoop:=0;
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143 | EndLoop:=Width+1;
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144 | END
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145 | ELSE
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146 | BEGIN
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147 | StartLoop:=Width+1;
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148 | EndLoop:=0;
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149 | END;
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150 |
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151 | WHILE StartLoop<>EndLoop DO
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152 | BEGIN
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153 | IF FDirection IN [dUp,dDown] THEN
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154 | BEGIN
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155 | rec.Left:=0;
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156 | rec.Right:=Width;
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157 | rec.Bottom:=StartLoop;
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158 | rec.Top:=rec.Bottom+1;
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159 | END
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160 | ELSE
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161 | BEGIN
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162 | rec.Left:=StartLoop;
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163 | rec.Right:=rec.Left+1;
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164 | rec.Bottom:=0;
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165 | rec.Top:=Height;
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166 | END;
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167 | Canvas.FillRect(rec,ValuesToRGB(Round(DRed),Round(DGreen),Round(DBlue)));
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168 |
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169 | DRed:=DRed+DR;
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170 | DGreen:=DGreen+DG;
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171 | DBlue:=DBlue+DB;
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172 |
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173 | IF FDirection IN [dUp,dLeft] THEN inc(StartLoop)
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174 | ELSE dec(StartLoop);
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175 | END;
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176 | END;
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177 | END; //case
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178 |
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179 | Canvas.Pen.Color:=SaveColor;
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180 | Canvas.DeleteClipRegion;
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181 | end;
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182 |
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183 | begin
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184 | RegisterClasses([TGradient]);
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185 | end.
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