如何在正确保持纵横比的情况下进行缩放 [英] How To Zoom with keeping aspect ratio correctly
问题描述
嗯,这就是我的目标.使用鼠标左键滚动图像,使用鼠标右键滚动选择缩放矩形并双击以恢复完全缩放.
Well this is my goal. Use left mouse button to scroll the image, right mouse button to choose zoom rectangle and doubleclick to restore full zoom.
我目前很累,到目前为止发现这与我加载图像或显示图像的方式无关,而是与它的绘制方式有关.无论窗体或源图像的形状如何,屏幕上的图像始终填充控件的客户区,因此不可能保留纵横比.我不知道如何改变这个或保持纵横比.从而给我一张干净漂亮的照片.
I have currently tired, so far found its NOT to do with the way i load the images or display the image but something with how it paints. The on-screen image always fills the control's client area regardless of the shape of the form or the source image, so the aspect ratio cannot possibly be preserved. I am not sure how to change this or keep the aspect ratio. Thus giving me a clean nice picture.
我正在发布我的 ZImage 单元的整个代码虽然我认为问题出在 Zimage.paint 或 Zimage.mouseup 但是我想如果你需要在其中一个函数中看到它会有助于将它全部发布.
I am posting the whole code for my ZImage unit Though i think the problem is either in the Zimage.paint or Zimage.mouseup But figured if you needed to see a function inside one of those it would help to have it all posted.
unit ZImage;
interface
uses
Windows, Messages, SysUtils,jpeg, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls;
type
TZImage = class(TGraphicControl)
private
FBitmap : Tbitmap;
PicRect : TRect;
ShowRect : TRect;
FShowBorder : boolean;
FBorderWidth : integer;
FForceRepaint : boolean;
FMouse : (mNone, mDrag, mZoom);
FProportional : boolean;
FDblClkEnable : boolean;
FLeft :integer;
FRight :integer;
FTop :integer;
FBottom :integer;
startx, starty,
oldx, oldy : integer;
procedure SetShowBorder(s:boolean);
procedure SetBitmap(b:TBitmap);
procedure SetBorderWidth(w:integer);
procedure SetProportional(b:boolean);
protected
procedure Paint; override;
procedure MouseDown(Button: TMouseButton; Shift: TShiftState;
X, Y: Integer); override;
procedure MouseMove(Shift: TShiftState; X, Y: Integer); override;
procedure MouseUp(Button: TMouseButton; Shift: TShiftState;
X, Y: Integer); override;
public
constructor Create(AOwner:TComponent); override;
destructor Destroy; override;
procedure DblClick; override;
published
procedure zoom(Endleft,EndRight,EndTop,EndBottom:integer);
property ValueLeft : integer read FLeft write FLeft;
property ValueRight : Integer read FRight write FRight;
Property ValueTop : Integer read FTop write FTop;
Property ValueBottom : Integer read FBottom write FBottom;
property ShowBorder : boolean
read FShowBorder
write SetShowBorder default true;
property KeepAspect : boolean
read FProportional
write SetProportional default true;
property Bitmap : TBitmap
read FBitmap
write Setbitmap;
property BorderWidth : integer
read FBorderWidth
write SetBorderWidth default 7;
property ForceRepaint : boolean
read FForceRepaint
write FForceRepaint default true;
property DblClkEnable : boolean
read FDblClkEnable
write FDblClkEnable default False;
property Align;
property Width;
property Height;
property Top;
property Left;
property Visible;
property Hint;
property ShowHint;
end;
procedure Register;
implementation
//This is the basic create options.
constructor TZImage.Create(AOwner:TComponent);
begin
inherited;
FShowBorder:=True;
FBorderWidth:=7;
FMouse:=mNone;
FForceRepaint:=true; //was true
FDblClkEnable:=False;
FProportional:=true; //was true
Width:=100; Height:=100;
FBitmap:=Tbitmap.Create;
FBitmap.Width:=width;
FBitmap.height:=Height;
ControlStyle:=ControlStyle+[csOpaque];
autosize:= false;
//Scaled:=false;
end;
//basic destroy frees the FBitmap
destructor TZImage.Destroy;
begin
FBitmap.Free;
inherited;
end;
//This was a custom zoom i was using to give the automated zoom effect
procedure TZimage.zoom(Endleft,EndRight,EndTop,EndBottom:integer);
begin
while ((Endbottom <> picrect.bottom) or (Endtop <> picrect.top)) or ((endleft <> picrect.left) or (endright <> picrect.right)) do
begin
if picrect.left > endleft then
picrect.left := picrect.left -1;
if picrect.left < endleft then //starting
picrect.left := picrect.left +1;
if picrect.right > endright then //starting
picrect.right := picrect.right -1;
if picrect.right < endright then
picrect.right := picrect.right +1;
if picrect.top > endtop then
picrect.top := picrect.top -1;
if picrect.top < endtop then //starting
picrect.top := picrect.top +1;
if picrect.bottom > endbottom then //starting
picrect.bottom := picrect.bottom -1;
if picrect.bottom < endbottom then
picrect.bottom := picrect.bottom +1;
self.refresh;
end;
end;
//this is the custom paint I know if i put
//Canvas.Draw(0,0,FBitmap); as the methond it displays
//perfect but the zoom option is gone of course and
//i need the Zoom.
procedure TZImage.Paint;
var buf:TBitmap;
coef,asps,aspp:Double;
sz,a : integer;
begin
buf:=TBitmap.Create;
buf.Width:=Width;
buf.Height:=Height;
if not FShowBorder
then ShowRect:=ClientRect
else ShowRect:=Rect(ClientRect.Left,ClientRect.Top,
ClientRect.Right-FBorderWidth,
ClientRect.Bottom-FBorderWidth);
ShowRect:=ClientRect;
with PicRect do begin
if Right=0 then Right:=FBitmap.Width;
if Bottom=0 then Bottom:=FBitmap.Height;
end;
buf.Canvas.CopyMode:=cmSrcCopy;
buf.Canvas.CopyRect(ShowRect,FBitmap.Canvas,PicRect);
Canvas.CopyMode:=cmSrcCopy;
Canvas.Draw(0,0,buf);
buf.Free;
end;
procedure TZImage.MouseDown(Button: TMouseButton; Shift: TShiftState;
X, Y: Integer);
begin
// if mbLeft<>Button then Exit;
if not PtInRect(ShowRect,Point(X,Y)) and
not PtInRect(Rect(ShowRect.Right,ShowRect.Bottom,
Width,Height),Point(X,Y)) then Exit;
if PtInRect(Rect(ShowRect.Right,ShowRect.Bottom,
Width,Height),Point(X,Y)) then begin
DblClick;
Exit;
end;
//here click is in the picture area only
startx:=x; oldx:=x;
starty:=y; oldy:=y;
if mbRight=Button then begin
MouseCapture:=True;
FMouse:=mZoom;
Canvas.Pen.Mode:=pmNot;
end else begin
FMouse:=mDrag;
Screen.Cursor:=crHandPoint;
end;
end;
function Min(a,b:integer):integer;
begin
if a<b then Result:=a else Result:=b;
end;
function Max(a,b:integer):integer;
begin
if a<b then Result:=b else Result:=a;
end;
procedure TZImage.MouseMove(Shift: TShiftState; X, Y: Integer);
var d,s:integer;
coef:Double;
begin
if FMouse=mNone then Exit;
if FMouse=mZoom then begin
Canvas.DrawFocusRect(Rect(Min(startx,oldx),Min(starty,oldy),Max(startx,oldx),Max(starty,oldy)));
oldx:=x; oldy:=y;
Canvas.DrawFocusRect(Rect(Min(startx,oldx),Min(starty,oldy),Max(startx,oldx),Max(starty,oldy)));
end;
if FMouse=mDrag then begin
//horizontal movement
coef:=(PicRect.Right-PicRect.Left)/(ShowRect.Right-ShowRect.Left);
d:=Round(coef*(x-oldx));
s:=PicRect.Right-PicRect.Left;
if d>0 then begin
if PicRect.Left>=d then begin
PicRect.Left:=PicRect.Left-d;
PicRect.Right:=PicRect.Right-d;
end else begin
PicRect.Left:=0;
PicRect.Right:=PicRect.Left+s;
end;
end;
if d<0 then begin
if PicRect.Right<FBitmap.Width+d then begin
PicRect.Left:=PicRect.Left-d;
PicRect.Right:=PicRect.Right-d;
end else begin
PicRect.Right:=FBitmap.Width;
PicRect.Left:=PicRect.Right-s;
end;
end;
//vertical movement
coef:=(PicRect.Bottom-PicRect.Top)/(ShowRect.Bottom-ShowRect.Top);
d:=Round(coef*(y-oldy));
s:=PicRect.Bottom-PicRect.Top;
if d>0 then begin
if PicRect.Top>=d then begin
PicRect.Top:=PicRect.Top-d;
PicRect.Bottom:=PicRect.Bottom-d;
end else begin
PicRect.Top:=0;
PicRect.Bottom:=PicRect.Top+s;
end;
end;
{There was a bug in the fragment below. Thanks to all, who reported this bug to me}
if d<0 then begin
if PicRect.Bottom<FBitmap.Height+d then begin
PicRect.Top:=PicRect.Top-d;
PicRect.Bottom:=PicRect.Bottom-d;
end else begin
PicRect.Bottom:=FBitmap.Height;
PicRect.Top:=PicRect.Bottom-s;
end;
end;
oldx:=x; oldy:=y;
if FForceRepaint then Repaint
else Invalidate;
end;
end;
procedure TZImage.MouseUp(Button: TMouseButton; Shift: TShiftState;
X, Y: Integer);
var coef:Double;
t:integer;
left,right,top,bottom : integer;
begin
if FMouse=mNone then Exit;
if x>ShowRect.Right then x:=ShowRect.Right;
if y>ShowRect.Bottom then y:=ShowRect.Bottom;
if FMouse=mZoom then begin //calculate new PicRect
t:=startx;
startx:=Min(startx,x);
x:=Max(t,x);
t:=starty;
starty:=Min(starty,y);
y:=Max(t,y);
FMouse:=mNone;
MouseCapture:=False;
//enable the following if you want to zoom-out by dragging in the opposite direction}
{ if Startx>x then begin
DblClick;
Exit;
end;}
if Abs(x-startx)<5 then Exit;
//showmessage('picrect Left='+inttostr(picrect.Left)+' right='+inttostr(picrect.Right)+' top='+inttostr(picrect.Top)+' bottom='+inttostr(picrect.Bottom));
//startx and start y is teh starting x/y of the selected area
//x and y is the ending x/y of the selected area
if (x - startx < y - starty) then
begin
while (x - startx < y - starty) do
begin
x := x + 100;
startx := startx - 100;
end;
end
else if (x - startx > y - starty) then
begin
while (x - startx > y - starty) do
begin
y := y + 100;
starty := starty - 100;
end;
end;
//picrect is the size of whole area
//PicRect.top and left are 0,0
//IFs were added in v.1.2 to avoid zero-divide
if (PicRect.Right=PicRect.Left)
then
coef := 100000
else
coef:=ShowRect.Right/(PicRect.Right-PicRect.Left); //if new screen coef= 1
left:=Round(PicRect.Left+startx/coef);
Right:=Left+Round((x-startx)/coef);
if (PicRect.Bottom=PicRect.Top)
then
coef := 100000
else
coef:=ShowRect.Bottom/(PicRect.Bottom-PicRect.Top);
Top:=Round(PicRect.Top+starty/coef);
Bottom:=Top+Round((y-starty)/coef);
//showmessage(inttostr(left)+' '+inttostr(Right)+' '+inttostr(top)+' '+inttostr(bottom));
zoom(left,right,top,bottom);
ValueLeft := left;
ValueRight := Right;
ValueTop := top;
ValueBottom := bottom;
end;
if FMouse=mDrag then begin
FMouse:=mNone;
Canvas.Pen.Mode:=pmCopy;
Screen.Cursor:=crDefault;
end;
Invalidate;
end;
procedure TZImage.DblClick;
begin
zoom(0,FBitMap.Width,0,FBitMap.Height);
ValueLeft := 0;
ValueRight := FBitMap.Width;
ValueTop := 0;
ValueBottom := FBitMap.Height;
//PicRect:=Rect(0,0,FBitmap.Width,FBitmap.Height);
Invalidate;
end;
procedure TZImage.SetBitmap(b:TBitmap);
begin
FBitmap.Assign(b);
PicRect:=Rect(0,0,b.Width, b.Height);
Invalidate;
end;
procedure TZImage.SetBorderWidth(w:integer);
begin
FBorderWidth:=w;
Invalidate;
end;
procedure TZImage.SetShowBorder(s:boolean);
begin
FShowBorder:=s;
Invalidate;
end;
procedure TZImage.SetProportional(b:boolean);
begin
FProportional:=b;
Invalidate;
end;
procedure Register;
begin
RegisterComponents('Custom', [TZImage]);
end;
end.
使用此代码,您可以注册组件 ZImage 并查看它如何运行...如果需要
With this code you can register the componet ZImage and see how it runs.. if needed
推荐答案
问题很清楚,但我认为回答它的问题是如何不重写完整的代码以使您能够理解.因为我更擅长编码而不是解释,所以我做到了.
The question is clear, but I think the problem answering it is how not to rewrite the complete code to be understandable for you. And since I am better at coding then explaining, I did.
我认为您正在搜索以下内容:
I think you are searching for something like the following:
unit ZImage2;
interface
uses
Windows, Messages, Classes, Controls, Graphics, StdCtrls, ExtCtrls, Math;
const
DefAnimDuration = 500;
type
TZImage = class(TGraphicControl)
private
FAlignment: TAlignment;
FAnimDuration: Cardinal;
FAnimRect: TRect;
FAnimStartTick: Cardinal;
FAnimTimer: TTimer;
FBuffer: TBitmap;
FCropRect: TRect;
FImgRect: TRect;
FLayout: TTextLayout;
FPicture: TPicture;
FPrevCropRect: TRect;
FProportional: Boolean;
FProportionalCrop: Boolean;
FScale: Single;
FSelColor: TColor;
FSelecting: Boolean;
FSelPoint: TPoint;
FSelRect: TRect;
procedure Animate(Sender: TObject);
function HasGraphic: Boolean;
procedure PictureChanged(Sender: TObject);
procedure RealignImage;
procedure SetAlignment(Value: TAlignment);
procedure SetLayout(Value: TTextLayout);
procedure SetPicture(Value: TPicture);
procedure SetProportional(Value: Boolean);
procedure UpdateBuffer;
protected
function CanAutoSize(var NewWidth, NewHeight: Integer): Boolean; override;
procedure ChangeScale(M: Integer; D: Integer); override;
procedure DblClick; override;
procedure MouseDown(Button: TMouseButton; Shift: TShiftState; X,
Y: Integer); override;
procedure MouseMove(Shift: TShiftState; X, Y: Integer); override;
procedure MouseUp(Button: TMouseButton; Shift: TShiftState; X,
Y: Integer); override;
procedure Paint; override;
procedure Resize; override;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
procedure Reset;
function ScreenToGraphic(R: TRect): TRect;
procedure Zoom(const ACropRect: TRect);
procedure ZoomSelection(const ASelRect: TRect);
published
property Alignment: TAlignment read FAlignment write SetAlignment
default taLeftJustify;
property AnimDuration: Cardinal read FAnimDuration write FAnimDuration
default DefAnimDuration;
property Layout: TTextLayout read FLayout write SetLayout default tlTop;
property Picture: TPicture read FPicture write SetPicture;
property Proportional: Boolean read FProportional write SetProportional
default False;
property ProportionalCrop: Boolean read FProportionalCrop
write FProportionalCrop default True;
property SelColor: TColor read FSelColor write FSelColor default clWhite;
published
property Align;
property Anchors;
property AutoSize;
property Color;
end;
implementation
function FitRect(const Boundary: TRect; Width, Height: Integer;
CanGrow: Boolean; HorzAlign: TAlignment; VertAlign: TTextLayout): TRect;
var
W: Integer;
H: Integer;
Scale: Single;
Offset: TPoint;
begin
Width := Max(1, Width);
Height := Max(1, Height);
W := Boundary.Right - Boundary.Left;
H := Boundary.Bottom - Boundary.Top;
if CanGrow then
Scale := Min(W / Width, H / Height)
else
Scale := Min(1, Min(W / Width, H / Height));
Result := Rect(0, 0, Round(Width * Scale), Round(Height * Scale));
case HorzAlign of
taLeftJustify:
Offset.X := 0;
taCenter:
Offset.X := (W - Result.Right) div 2;
taRightJustify:
Offset.X := W - Result.Right;
end;
case VertAlign of
tlTop:
Offset.Y := 0;
tlCenter:
Offset.Y := (H - Result.Bottom) div 2;
tlBottom:
Offset.Y := H - Result.Bottom;
end;
OffsetRect(Result, Boundary.Left + Offset.X, Boundary.Top + Offset.Y);
end;
function NormalizeRect(const Point1, Point2: TPoint): TRect;
begin
Result.Left := Min(Point1.X, Point2.X);
Result.Top := Min(Point1.Y, Point2.Y);
Result.Right := Max(Point1.X, Point2.X);
Result.Bottom := Max(Point1.Y, Point2.Y);
end;
{ TZImage }
procedure TZImage.Animate(Sender: TObject);
var
Done: Single;
begin
Done := (GetTickCount - FAnimStartTick) / FAnimDuration;
if Done >= 1.0 then
begin
FAnimTimer.Enabled := False;
FAnimRect := FCropRect;
end
else
with FPrevCropRect do
FAnimRect := Rect(
Left + Round(Done * (FCropRect.Left - Left)),
Top + Round(Done * (FCropRect.Top - Top)),
Right + Round(Done * (FCropRect.Right - Right)),
Bottom + Round(Done * (FCropRect.Bottom - Bottom)));
UpdateBuffer;
RealignImage;
Invalidate;
end;
function TZImage.CanAutoSize(var NewWidth, NewHeight: Integer): Boolean;
begin
Result := True;
if not (csDesigning in ComponentState) or HasGraphic then
begin
if Align in [alNone, alLeft, alRight] then
NewWidth := Round(FScale * FPicture.Width);
if Align in [alNone, alTop, alBottom] then
NewHeight := Round(FScale * FPicture.Height);
end;
end;
procedure TZImage.ChangeScale(M, D: Integer);
var
SaveAnchors: TAnchors;
begin
SaveAnchors := Anchors;
Anchors := [akLeft, akTop];
FScale := FScale * M / D;
inherited ChangeScale(M, D);
Anchors := SaveAnchors;
end;
constructor TZImage.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
ControlStyle := [csCaptureMouse, csClickEvents, csOpaque, csDoubleClicks];
FAnimTimer := TTimer.Create(Self);
FAnimTimer.Interval := 15;
FAnimTimer.OnTimer := Animate;
FAnimDuration := DefAnimDuration;
FBuffer := TBitmap.Create;
FPicture := TPicture.Create;
FPicture.OnChange := PictureChanged;
FProportionalCrop := True;
FScale := 1.0;
FSelColor := clWhite;
end;
procedure TZImage.DblClick;
begin
if not HasGraphic then
Reset
else
Zoom(Rect(0, 0, FPicture.Width, FPicture.Height));
inherited DblClick;
end;
destructor TZImage.Destroy;
begin
FPicture.Free;
FBuffer.Free;
inherited Destroy;
end;
function TZImage.HasGraphic: Boolean;
begin
Result := (Picture.Width > 0) and (Picture.Height > 0);
end;
procedure TZImage.MouseDown(Button: TMouseButton; Shift: TShiftState; X,
Y: Integer);
begin
if (Button = mbRight) and HasGraphic and PtInRect(FImgRect, Point(X, Y)) then
begin
FSelPoint.X := X;
FSelPoint.Y := Y;
FSelRect := Rect(X, Y, X, Y);
FSelecting := True;
Canvas.Brush.Color := FSelColor;
Canvas.DrawFocusRect(FSelRect);
end;
inherited MouseDown(Button, Shift, X, Y);
end;
procedure TZImage.MouseMove(Shift: TShiftState; X, Y: Integer);
const
HorzAlign: array[Boolean] of TAlignment = (taLeftJustify, taRightJustify);
VertAlign: array[Boolean] of TTextLayout = (tlTop, tlBottom);
begin
if FSelecting and PtInRect(FImgRect, Point(X, Y)) then
begin
Canvas.DrawFocusRect(FSelRect);
FSelRect := NormalizeRect(FSelPoint, Point(X, Y));
if (not FProportionalCrop) then
FSelRect := FitRect(FSelRect, FPicture.Graphic.Width,
FPicture.Graphic.Height, True, HorzAlign[X < FSelPoint.X],
VertAlign[Y < FSelPoint.Y]);
Canvas.DrawFocusRect(FSelRect);
end;
inherited MouseMove(Shift, X, Y);
end;
procedure TZImage.MouseUp(Button: TMouseButton; Shift: TShiftState; X,
Y: Integer);
begin
if FSelecting then
begin
FSelecting := False;
Canvas.DrawFocusRect(FSelRect);
if (Abs(X - FSelPoint.X) > Mouse.DragThreshold) or
(Abs(Y - FSelPoint.Y) > Mouse.DragThreshold) then
ZoomSelection(FSelRect);
end;
inherited MouseUp(Button, Shift, X, Y);
end;
procedure TZImage.Paint;
begin
Canvas.Brush.Color := Color;
if HasGraphic then
begin
Canvas.StretchDraw(FImgRect, FBuffer);
if FSelecting then
Canvas.DrawFocusRect(FSelRect);
with FImgRect do
ExcludeClipRect(Canvas.Handle, Left, Top, Right, Bottom);
end;
Canvas.FillRect(Canvas.ClipRect);
end;
procedure TZImage.PictureChanged(Sender: TObject);
begin
Reset;
end;
procedure TZImage.RealignImage;
begin
if not HasGraphic then
FImgRect := Rect(0, 0, 0, 0)
else if FProportional then
FImgRect := ClientRect
else
FImgRect := FitRect(ClientRect, FBuffer.Width, FBuffer.Height, True,
FAlignment, FLayout);
end;
procedure TZImage.Reset;
begin
FCropRect := Rect(0, 0, FPicture.Width, FPicture.Height);
FAnimRect := FCropRect;
UpdateBuffer;
RealignImage;
Invalidate;
end;
procedure TZImage.Resize;
begin
RealignImage;
inherited Resize;
end;
function TZImage.ScreenToGraphic(R: TRect): TRect;
var
CropWidth: Integer;
CropHeight: Integer;
ImgWidth: Integer;
ImgHeight: Integer;
begin
CropWidth := FCropRect.Right - FCropRect.Left;
CropHeight := FCropRect.Bottom - FCropRect.Top;
ImgWidth := FImgRect.Right - FImgRect.Left;
ImgHeight := FImgRect.Bottom - FImgRect.Top;
IntersectRect(R, R, FImgRect);
OffsetRect(R, -FImgRect.Left, -FImgRect.Top);
Result := Rect(
FCropRect.Left + Round(CropWidth * (R.Left / ImgWidth)),
FCropRect.Top + Round(CropHeight * (R.Top / ImgHeight)),
FCropRect.Left + Round(CropWidth * (R.Right / ImgWidth)),
FCropRect.Top + Round(CropHeight * (R.Bottom / ImgHeight)));
end;
procedure TZImage.SetAlignment(Value: TAlignment);
begin
if FAlignment <> Value then
begin
FAlignment := Value;
RealignImage;
Invalidate;
end;
end;
procedure TZImage.SetLayout(Value: TTextLayout);
begin
if FLayout <> Value then
begin
FLayout := Value;
RealignImage;
Invalidate;
end;
end;
procedure TZImage.SetPicture(Value: TPicture);
begin
FPicture.Assign(Value);
end;
procedure TZImage.SetProportional(Value: Boolean);
begin
if FProportional <> Value then
begin
FProportional := Value;
RealignImage;
Invalidate;
end;
end;
procedure TZImage.UpdateBuffer;
begin
if HasGraphic then
begin
FBuffer.Width := FAnimRect.Right - FAnimRect.Left;
FBuffer.Height := FAnimRect.Bottom - FAnimRect.Top;
FBuffer.Canvas.Draw(-FAnimRect.Left, -FAnimRect.Top, FPicture.Graphic);
end;
end;
procedure TZImage.Zoom(const ACropRect: TRect);
begin
if HasGraphic then
begin
FPrevCropRect := FAnimRect;
FCropRect := ACropRect;
if FAnimDuration = 0 then
begin
FAnimRect := FCropRect;
UpdateBuffer;
RealignImage;
Invalidate;
end
else
begin
FAnimStartTick := GetTickCount;
FAnimTimer.Enabled := True;
end;
end;
end;
procedure TZImage.ZoomSelection(const ASelRect: TRect);
begin
Zoom(ScreenToGraphic(ASelRect));
end;
end.
示例代码:
procedure TForm1.FormCreate(Sender: TObject);
begin
FImage := TZImage.Create(Self);
FImage.SetBounds(10, 10, 200, 300);
FImage.Picture.LoadFromFile('D:PicturesMona_Lisa.jpg');
FImage.Alignment := taCenter;
FImage.Layout := tlCenter;
FImage.AutoSize := True;
FImage.Parent := Self;
end;
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