再学 GDI+[42]: 文本输出 - 字号单位

本例效果图:

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代码文件:

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unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, ComCtrls;

type
  TForm1 = class(TForm)
    RadioGroup1: TRadioGroup;
    TrackBar1: TTrackBar;
    procedure FormCreate(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure RadioGroup1Click(Sender: TObject);
    procedure TrackBar1Change(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GDIPOBJ,GDIPAPI,TypInfo;

procedure TForm1.FormCreate(Sender: TObject);
var
  i: Integer;
begin
  for i := 0 to 6 do
    RadioGroup1.Items.Add(GetEnumName(TypeInfo(TUnit), i));
  RadioGroup1.ItemIndex := 2;

  RadioGroup1.Buttons[0].Enabled := False;
  RadioGroup1.Buttons[1].Enabled := False;
  RadioGroup1.Buttons[4].Enabled := False;
  RadioGroup1.Buttons[5].Enabled := False;

  TrackBar1.ShowSelRange := False;
  TrackBar1.Min := 1;
  TrackBar1.Max := 100;
  TrackBar1.Position := 22;
end;

procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
  b: TGPBrush;
  font: TGPFont;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  b := TGPSolidBrush.Create(aclDarkOrange);

  font := TGPFont.Create('Arial Black',
                          TrackBar1.Position,
                          FontStyleBoldItalic,
                          TUnit(RadioGroup1.ItemIndex) {字号单位, 默认是像素: UnitPixel}
                        );
  g.DrawString('Delphi', -1, font, MakePoint(5.0, 5), b);

  b.Free;
  font.Free;
  g.Free;
end;

procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
  Repaint;
end;

procedure TForm1.TrackBar1Change(Sender: TObject);
begin
  Repaint;
  Text := IntToStr(TrackBar1.Position);
  TrackBar1.Refresh;
end;

end.

窗体文件:

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object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 147
  ClientWidth = 336
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnCreate = FormCreate
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
  object RadioGroup1: TRadioGroup
    Left = 237
    Top = 0
    Width = 99
    Height = 147
    Align = alRight
    Caption = 'RadioGroup1'
    TabOrder = 0
    OnClick = RadioGroup1Click
    ExplicitLeft = 240
  end
  object TrackBar1: TTrackBar
    Left = 0
    Top = 126
    Width = 241
    Height = 45
    TabOrder = 1
    OnChange = TrackBar1Change
  end
end

坐标单位类型表:

Delphi	微软	说明
UnitWorld	World	将世界坐标系单位指定为度量单位。
UnitDisplay	Display	指定显示设备的度量单位。通常，视频显示使用的单位是像素；打印机使用的单位是 1/100 英寸。
UnitPixel	Pixel	将设备像素指定为度量单位。
UnitPoint	Point	将打印机点（1/72 英寸）指定为度量单位。
UnitInch	Inch	将英寸指定为度量单位。
UnitDocument	Document	将文档单位（1/300 英寸）指定为度量单位。
UnitMillimeter	Millimeter	将毫米指定为度量单位。

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