本文以实例介绍了Delphi实现图片滚动切换的方法。该程序可以实现图像的滚动播出，并且通过本代码可控制窗口中的图像向上滚动，通过调节速度滚动条的值还可以调整滚动的速度；点击“停止”按钮，图像即停止滚动。
完整的功能代码如下：
unit Unit1;
interface
uses
Windows, Classes, Graphics, Forms, Controls, Menus,
Dialogs, StdCtrls, ExtCtrls, SysUtils, ComCtrls, Buttons;
type
TForm1 = class(TForm)
MainMenu1: TMainMenu;
File1: TMenuItem;
Open1: TMenuItem;
N1: TMenuItem;
Exit1: TMenuItem;
Help1: TMenuItem;
AboutImageViewer1: TMenuItem;
OpenDialog1: TOpenDialog;
Options1: TMenuItem;
ColorDepth1: TMenuItem;
ScrollPanel1: TMenuItem;
Panel1: TPanel;
TrackBar1: TTrackBar;
BitBtn2: TBitBtn;
BitBtn1: TBitBtn;
Label1: TLabel;
Image1: TImage;
N2: TMenuItem;
procedure Open1Click(Sender: TObject);
procedure Exit1Click(Sender: TObject);
procedure AboutImageViewer1Click(Sender: TObject);
procedure ColorDepth1Click(Sender: TObject);
procedure ScrollPanel1Click(Sender: TObject);
procedure TrackBar1Change(Sender: TObject);
procedure BitBtn1Click(Sender: TObject);
procedure BitBtn2Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
private
public
{ Public declarations }
end;
var
Form1: TForm1;
nLines: Integer;
fCancel: Boolean;
implementation
{$R *.DFM}
procedure TForm1.Open1Click(Sender: TObject);
begin
if OpenDialog1.Execute then
begin
Image1.Picture.LoadFromFile (OpenDialog1.FileName);//导入图像文件
Caption := '控制图像动态移动- ' + OpenDialog1.FileName;//改变窗体标题
end;
end;
procedure TForm1.Exit1Click(Sender: TObject);
begin
Close; //退出窗体
end;
procedure TForm1.AboutImageViewer1Click(Sender: TObject);//关于
begin
MessageDlg ('控制图像动态移动为'+ #13'Delphi图形工作室制作', mtInFormation,
[mbOk], 0);
end;
procedure TForm1.ColorDepth1Click(Sender: TObject);
var
strDepth: String;
begin
case Image1.Picture.Bitmap.PixelFormat of //获得图像颜色深度
pfDevice: strDepth := '无图';
pf1bit: strDepth := '1-bit';
pf4bit: strDepth := '4-bit';
pf8bit: strDepth := '8-bit';
pf15bit: strDepth := '15-bit';
pf16bit: strDepth := '16-bit';
pf24bit: strDepth := '24-bit';
pf32bit: strDepth := '32-bit';
pfCustom: strDepth := 'Custom';
end;
MessageDlg ('图像颜色深度：' + strDepth,mtInFormation, [mbOK], 0);//给出图像
颜色深度信息
end;
procedure TForm1.ScrollPanel1Click(Sender: TObject);
begin
Panel1.Visible := not Panel1.Visible;
ScrollPanel1.Checked := Panel1.Visible; //改变控制面板的可见性
end;
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
nLines := TrackBar1.Position;
TrackBar1.Hint := IntToStr (TrackBar1.Position);//给出当前速度大小的提示
end;
procedure TForm1.BitBtn1Click(Sender: TObject);
var
W, H, I, J, LineBytes: Integer;
Line: PByteArray; //定义指针类型变量
Bmp: Tbitmap;
R: TRect;
begin
if Image1.Picture.Bitmap.PixelFormat=pfDevice then //当没有打开图片时
begin
MessageDlg ('没有打开图片！', mtInFormation, [mbOk], 0);//给出出错提示
exit; //退出
end
else
fCancel := False;
BitBtn1.Enabled := False; //改变两个按钮的属性
BitBtn2.Enabled := True;
Bmp := Image1.Picture.Bitmap; //获取BMP 图像并定义图像尺寸
W := Bmp.Width;
H := Bmp.Height;
LineBytes := Abs (Integer (Bmp.ScanLine [1]) -Integer (Bmp.ScanLine [0]));
Line := AllocMem (LineBytes);
for I := 0 to H - 1 do
begin
if fCancel then //在每一次循环前均检查中断标志（即确定停止按钮是否按下）
Break; //单击“停止”按钮则停止滚动图像
Move ((Bmp.ScanLine [0]), Line, LineBytes); //复制图像的第一行
for J := 1 to H - 1 do
begin
Move ((Bmp.ScanLine [J]), (Bmp.ScanLine [J-1]), LineBytes);
if (J mod nLines = 0) then
begin
R := Rect (0, Panel1.Height + J-nLines,W, Panel1.Height + J);
InvalidateRect (Handle, @R, False);
UpdateWindow (Handle);
end;
end;
Move (Line, (Bmp.ScanLine [Bmp.Height - 1]), LineBytes);
R := Rect (0, Panel1.Height + H - nLines,W, Panel1.Height + H);
InvalidateRect (Handle, @R, False);
UpdateWindow (Handle);
Application.ProcessMessages; //允许立即停止循环使程序处于初始状态
end;
BitBtn1.Enabled := True; //激活“开始”按钮
BitBtn2.Enabled := False; // 停止“按钮”失效
end;
procedure TForm1.BitBtn2Click(Sender: TObject);
begin
fCancel := True; //改变标志Fcancel 的值，停止图像滚动
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
TrackBar1Change (self); //调用TrackBar1Change 函数
end;
end.
