| [15] | 1 | Unit RichTextDisplayUnit;
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| 2 |
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| 3 | Interface
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| 4 |
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| 5 | uses
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| 6 | Classes,
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| 7 | CanvasFontManager,
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| 8 | RichTextStyleUnit, RichTextLayoutUnit;
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| 9 |
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| 10 | // Selection start and end should both be nil if no selection is to be applied
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| 11 | Procedure DrawRichTextLayout( const FontManager: TCanvasFontManager;
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| 12 | const Layout: TRichTextLayout;
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| 13 | const SelectionStart: PChar;
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| 14 | const SelectionEnd: PChar;
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| 15 | const StartLine: longint;
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| 16 | const EndLine: longint;
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| 17 | const StartPoint: TPoint );
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| 18 |
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| 19 | // Print as much of the given layout as will fit on the page,
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| 20 | // starting at StartY and StartLine
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| 21 | // EndY is set to the final Y output position used + 1.
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| 22 | // EndLine is set to the last line printed + 1
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| 23 | Procedure PrintRichTextLayout( const FontManager: TCanvasFontManager;
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| 24 | const Layout: TRichTextLayout;
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| 25 | const StartLine: longint;
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| 26 | var EndLine: longint;
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| 27 | const StartY: longint;
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| 28 | var EndY: longint );
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| 29 |
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| 30 | Implementation
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| 31 |
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| 32 | uses
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| 33 | SysUtils,
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| 34 | Forms, Graphics,
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| 35 | ACLString, ACLUtility,
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| 36 | RichTextDocumentUnit;
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| 37 |
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| 38 | // For the given point in the text, update selected if the point
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| 39 | // is at start or end of selection
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| 40 | // Returns true if changed
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| 41 | function SelectionChange( P: PChar;
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| 42 | SelectionStart: PChar;
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| 43 | SelectionEnd: PChar;
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| 44 | var NextSelected: boolean ): boolean;
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| 45 | begin
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| 46 | Result := false;
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| 47 | if P = SelectionStart then
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| 48 | begin
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| 49 | Result := true;
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| 50 | if SelectionStart < SelectionEnd then
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| 51 | // reached start of selection
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| 52 | NextSelected := true
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| 53 | else
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| 54 | // reached end
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| 55 | NextSelected := false;
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| 56 | end
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| 57 | else if P = SelectionEnd then
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| 58 | begin
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| 59 | Result := true;
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| 60 | if SelectionStart < SelectionEnd then
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| 61 | // reached end of selection
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| 62 | NextSelected := false
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| 63 | else
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| 64 | // reached start
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| 65 | NextSelected := true;
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| 66 | end;
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| 67 | end;
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| 68 |
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| 69 | function InvertRGB( Arg: TColor ): TColor;
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| 70 | begin
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| 71 | Result := SysColorToRGB( Arg ); // in case it's a system color e.g. button face
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| 72 | Result := Result xor $ffffff; // now invert the RGB components
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| 73 | end;
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| 74 |
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| 75 | // Draw a string at the given location with given color/selected state
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| 76 | Procedure DrawRichTextString( FontManager: TCanvasFontManager;
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| 77 | Var X: longint;
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| 78 | Y: longint;
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| 79 | S: PChar;
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| 80 | Len: longint;
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| 81 | Selected: Boolean;
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| 82 | PenColor: TColor;
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| 83 | BackColor: TColor );
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| 84 | var
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| 85 | Point: TPoint;
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| 86 | begin
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| 87 | if Len = 0 then
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| 88 | exit;
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| 89 |
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| 90 | Point.X := X;
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| 91 | Point.Y := Y;
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| 92 | { if FDebug then
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| 93 | begin
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| 94 | // generate a random dark color
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| 95 | Canvas.Brush.Color := random( 191 ) * 65536 //r
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| 96 | + random( 191 ) * 256 //g
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| 97 | + random( 191 ); //b
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| 98 | Canvas.Pen.Color := clWhite;
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| 99 | end
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| 100 | else}
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| 101 |
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| 102 | if Selected then
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| 103 | begin
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| 104 | FontManager.Canvas.Brush.Color := InvertRGB( BackColor );
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| 105 | FontManager.Canvas.Pen.Color := InvertRGB( PenColor );
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| 106 | end
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| 107 | else
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| 108 | begin
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| 109 | FontManager.Canvas.Brush.Color := BackColor;
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| 110 | FontManager.Canvas.Pen.Color := PenColor;
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| 111 | end;
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| 112 | FontManager.DrawString( Point, Len, S );
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| 113 | X := Point.X;
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| 114 | end;
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| 115 |
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| 116 | var
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| 117 | // global, so that we don't reallocate every drawline
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| 118 | StringToDraw: TAString = nil;
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| 119 |
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| 120 | // Draw the specified line at the specified
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| 121 | // (physical) location
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| 122 | Procedure DrawRichTextLine( FontManager: TCanvasFontManager;
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| 123 | Layout: TRichTextLayout;
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| 124 | SelectionStart: PChar;
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| 125 | SelectionEnd: PChar;
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| 126 |
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| 127 | Line: TLayoutLine;
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| 128 | Start: TPoint );
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| 129 | var
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| 130 | X, Y: longint;
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| 131 | Element: TTextElement;
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| 132 | StartedDrawing: boolean;
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| 133 | Style: TTextDrawStyle;
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| 134 | P: PChar;
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| 135 | NextP: PChar;
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| 136 | EndP: PChar;
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| 137 |
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| 138 | BitmapIndex: longint;
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| 139 | Bitmap: TBitmap;
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| 140 |
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| 141 | BitmapRect: TRect;
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| 142 |
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| 143 | TextBlockStart: PChar;
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| 144 |
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| 145 | Selected: boolean;
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| 146 | NextSelected: boolean;
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| 147 |
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| 148 | NewMarginX: longint;
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| 149 |
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| 150 | procedure DrawTextBlock;
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| 151 | var
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| 152 | PhysX: longint;
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| 153 | begin
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| 154 | PhysX := X div FontWidthPrecisionFactor;
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| 155 |
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| 156 | DrawRichTextString( FontManager,
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| 157 | PhysX,
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| 158 | Y,
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| 159 | StringToDraw.AsPChar,
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| 160 | StringToDraw.Length,
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| 161 | Selected,
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| 162 | Style.Color,
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| 163 | Style.BackgroundColor );
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| 164 | X := PhysX * FontWidthPrecisionFactor;
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| 165 | StringToDraw.AssignString( '' );
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| 166 | end;
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| 167 |
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| 168 |
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| 169 | begin
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| 170 | P := Line.Text;
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| 171 | EndP := Line.Text + Line.Length;
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| 172 |
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| 173 | if P = EndP then
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| 174 | begin
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| 175 | // Empty line
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| 176 | exit;
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| 177 | end;
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| 178 |
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| 179 | Selected := false;
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| 180 | if SelectionStart <= Line.Text then
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| 181 | // selection start is above.
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| 182 | Selected := true;
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| 183 | if SelectionEnd <= Line.Text then
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| 184 | // selection end is above.
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| 185 | Selected := not Selected;
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| 186 |
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| 187 | if StringToDraw = nil then
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| 188 | StringToDraw := TAString.Create;
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| 189 |
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| 190 | Style := Line.Style;
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| 191 | FontManager.SetFont( Style.Font );
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| 192 | StartedDrawing := false;
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| 193 |
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| 194 | TextBlockStart := P;
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| 195 |
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| 196 | Y := Start.Y + Line.MaxDescender;
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| 197 |
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| 198 | while P < EndP do
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| 199 | begin
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| 200 | Element := ExtractNextTextElement( P, NextP );
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| 201 |
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| 202 | if SelectionChange( P,
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| 203 | SelectionStart,
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| 204 | SelectionEnd,
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| 205 | NextSelected ) then
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| 206 | begin
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| 207 | DrawTextBlock;
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| 208 | TextBlockStart := P;
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| 209 | Selected := NextSelected;
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| 210 | end;
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| 211 |
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| 212 | case Element.ElementType of
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| 213 | teWordBreak,
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| 214 | teText,
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| 215 | teImage:
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| 216 | begin
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| 217 | if not StartedDrawing then
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| 218 | begin
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| 219 | // we haven't yet started drawing:
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| 220 | // so work out alignment
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| 221 | X := Start.X * FontWidthPrecisionFactor
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| 222 | + Layout.GetStartX( Style, Line );
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| 223 | StartedDrawing := true;
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| 224 | end;
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| 225 |
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| 226 | // Now do the drawing
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| 227 | if Element.ElementType = teImage then
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| 228 | begin
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| 229 | DrawTextBlock;
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| 230 | TextBlockStart := NextP;
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| 231 |
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| 232 | try
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| 233 | BitmapIndex := StrToInt( Element.Tag.Arguments );
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| 234 | except
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| 235 | BitmapIndex := -1;
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| 236 | end;
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| 237 | if Layout.IsValidBitmapIndex( BitmapIndex ) then
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| 238 | begin
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| 239 | Bitmap := Layout.Images.GetBitmapReference( BitmapIndex );
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| 240 |
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| 241 | BitmapRect.Left := X div FontWidthPrecisionFactor;
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| 242 | BitmapRect.Bottom := Start.Y;
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| 243 | BitmapRect.Right := BitmapRect.Left
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| 244 | + Bitmap.Width
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| 245 | * Layout.HorizontalImageScale;
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| 246 | BitmapRect.Top := BitmapRect.Bottom
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| 247 | + Bitmap.Height
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| 248 | * Layout.VerticalImageScale;;
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| 249 |
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| 250 | Bitmap.Draw( FontManager.Canvas,
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| 251 | BitmapRect );
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| 252 |
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| 253 |
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| 254 | inc( X,
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| 255 | trunc( Bitmap.Width
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| 256 | * FontWidthPrecisionFactor
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| 257 | * Layout.HorizontalImageScale ) );
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| 258 | end;
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| 259 | end
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| 260 | else
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| 261 | begin
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| 262 | // character (or word break)
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| 263 | // build up the successive characters...
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| 264 | StringToDraw.AddString( Element.Character );
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| 265 | end;
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| 266 | end;
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| 267 |
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| 268 | teStyle:
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| 269 | begin
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| 270 | DrawTextBlock;
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| 271 | TextBlockStart := NextP;
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| 272 |
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| 273 | if ( Element.Tag.TagType = ttItalicOff )
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| 274 | and ( faItalic in Style.Font.Attributes )
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| 275 | and ( not FontManager.IsFixed )
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| 276 | then
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| 277 | // end of italic; add a space
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| 278 | inc( X, FontManager.CharWidth( ' ' ) );
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| 279 |
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| 280 | Layout.PerformStyleTag( Element.Tag,
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| 281 | Style,
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| 282 | X );
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| 283 | NewMarginX := ( Start.X + Style.LeftMargin ) * FontWidthPrecisionFactor;
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| 284 | if NewMarginX > X then
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| 285 | begin
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| 286 | //skip across...
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| 287 | X := NewMarginX;
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| 288 | end;
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| 289 | end;
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| 290 | end;
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| 291 | P := NextP;
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| 292 | end;
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| 293 |
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| 294 | DrawTextBlock;
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| 295 | end;
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| 296 |
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| 297 | Procedure DrawRichTextLayout( const FontManager: TCanvasFontManager;
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| 298 | const Layout: TRichTextLayout;
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| 299 | const SelectionStart: PChar;
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| 300 | const SelectionEnd: PChar;
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| 301 | const StartLine: longint;
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| 302 | const EndLine: longint;
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| 303 | const StartPoint: TPoint );
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| 304 | Var
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| 305 | Line: TLayoutLine;
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| 306 | LineIndex: longint;
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| 307 |
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| 308 | Y: longint;
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| 309 |
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| 310 | BottomOfLine: longint;
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| 311 | begin
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| 312 | assert( StartLine >= 0 );
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| 313 | assert( StartLine <= Layout.FNumLines );
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| 314 | assert( EndLine >= 0 );
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| 315 | assert( EndLine <= Layout.FNumLines );
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| 316 | assert( StartLine <= EndLine );
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| 317 |
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| 318 | if Layout.FNumLines = 0 then
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| 319 | // no text to draw
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| 320 | exit;
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| 321 |
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| 322 | Y := StartPoint.Y
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| 323 | - Layout.FRichTextSettings.Margins.Top;
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| 324 |
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| 325 | LineIndex := 0;
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| 326 |
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| 327 | repeat
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| 328 | Line := Layout.FLines[ LineIndex ];
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| 329 | BottomOfLine := Y - Line.Height + 1; // bottom pixel row is top - height + 1
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| 330 |
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| 331 | if // the line is in the range to be drawn
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| 332 | ( LineIndex >= StartLine )
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| 333 | and ( LineIndex <= EndLine )
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| 334 |
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| 335 | // and the line is within the cliprect
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| 336 | and ( BottomOfLine <= FontManager.Canvas.ClipRect.Top )
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| 337 | and ( Y > FontManager.Canvas.ClipRect.Bottom ) then
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| 338 | begin
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| 339 | // draw it. First decided whether selection is started or not.
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| 340 | DrawRichTextLine( FontManager,
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| 341 | Layout,
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| 342 | SelectionStart,
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| 343 | SelectionEnd,
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| 344 | Line,
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| 345 | Point( StartPoint.X,
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| 346 | BottomOfLine ) );
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| 347 |
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| 348 | end;
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| 349 | dec( Y, Line.Height );
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| 350 |
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| 351 | if Y < 0 then
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| 352 | // past bottom of output canvas
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| 353 | break;
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| 354 |
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| 355 | inc( LineIndex );
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| 356 |
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| 357 | if LineIndex >= Layout.FNumLines then
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| 358 | // end of text
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| 359 | break;
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| 360 |
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| 361 | until false;
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| 362 |
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| 363 | End;
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| 364 |
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| 365 | Procedure PrintRichTextLayout( const FontManager: TCanvasFontManager;
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| 366 | const Layout: TRichTextLayout;
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| 367 | const StartLine: longint;
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| 368 | var EndLine: longint;
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| 369 | const StartY: longint;
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| 370 | var EndY: longint );
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| 371 | Var
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| 372 | Selected: boolean;
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| 373 | Line: TLayoutLine;
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| 374 | LineIndex: longint;
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| 375 |
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| 376 | Y: longint;
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| 377 |
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| 378 | BottomOfLine: longint;
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| 379 |
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| 380 | LinesPrinted: longint;
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| 381 | begin
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| 382 | assert( StartLine >= 0 );
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| 383 | assert( StartLine <= Layout.FNumLines );
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| 384 |
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| 385 | if Layout.FNumLines = 0 then
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| 386 | // no text to draw
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| 387 | exit;
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| 388 |
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| 389 | Y := StartY;
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| 390 | // - Layout.FRichTextSettings.Margins.Top;
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| 391 |
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| 392 | Selected := false; // it's not going to change.
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| 393 |
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| 394 | LinesPrinted := 0;
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| 395 |
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| 396 | LineIndex := StartLine;
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| 397 |
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| 398 | repeat
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| 399 | Line := Layout.FLines[ LineIndex ];
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| 400 | BottomOfLine := Y - Line.Height + 1; // bottom pixel row is top - height + 1
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| 401 |
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| 402 | if BottomOfLine < Layout.FRichTextSettings.Margins.Bottom then
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| 403 | // past bottom of page (less margin)
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| 404 | if LinesPrinted > 0 then
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| 405 | // stop, as long as we've printed at least 1 line
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| 406 | break;
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| 407 |
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| 408 | // draw it
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| 409 | DrawRichTextLine( FontManager,
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| 410 | Layout,
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| 411 | nil,
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| 412 | nil,
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| 413 | Line,
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| 414 | Point( 0,
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| 415 | BottomOfLine ) );
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| 416 |
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| 417 | dec( Y, Line.Height );
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| 418 |
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| 419 | inc( LinesPrinted );
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| 420 |
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| 421 | inc( LineIndex );
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| 422 |
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| 423 | if LineIndex >= Layout.FNumLines then
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| 424 | // end of text
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| 425 | break;
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| 426 |
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| 427 | until false;
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| 428 |
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| 429 | EndY := Y;
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| 430 | EndLine := LineIndex;
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| 431 | End;
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| 432 |
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| 433 | Initialization
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| 434 | End.
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