经过一些关于如何捕获父控件背景的研究,我根据FMX中TMagnifierGlass类编写了以下代码(请注意,我在XE5中编写了此代码,您需要检查XE6的兼容性):
TGlass = class(TControl)
private
FBlur: TBlurEffect;
FParentScreenshotBitmap: TBitmap;
function GetSoftness: Single;
procedure SetSoftness(Value: Single);
protected
procedure Paint; override;
public
constructor Create(AOwner: TComponent);
destructor Destroy; override;
property Softness: Single read GetSoftness write SetSoftness;
end;
constructor TGlass.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FParentScreenshotBitmap := TBitmap.Create(0, 0);
FBlur := TBlurEffect.Create(nil);
FBlur.Softness := 0.6;
end;
destructor TGlass.Destroy;
begin
FBlur.Free;
FParentScreenshotBitmap.Free;
inherited Destroy;
end;
function TGlass.GetSoftness: Single;
begin
Result := FBlur.Softness;
end;
procedure TGlass.SetSoftness(Value: Single);
begin
FBlur.Softness := Value;
end;
procedure TGlass.Paint;
var
ParentWidth: Single;
ParentHeight: Single;
procedure DefineParentSize;
begin
ParentWidth := 0;
ParentHeight := 0;
if Parent is TCustomForm then
begin
ParentWidth := (Parent as TCustomForm).ClientWidth;
ParentHeight := (Parent as TCustomForm).ClientHeight;
end;
if Parent is TControl then
begin
ParentWidth := (Parent as TControl).Width;
ParentHeight := (Parent as TControl).Height;
end;
end;
function IsBitmapSizeChanged(ABitmap: TBitmap; const ANewWidth, ANewHeight: Single): Boolean;
begin
Result := not SameValue(ANewWidth * ABitmap.BitmapScale, ABitmap.Width) or
not SameValue(ANewHeight * ABitmap.BitmapScale, ABitmap.Height);
end;
procedure MakeParentScreenshot;
var
Form: TCommonCustomForm;
Child: TFmxObject;
ParentControl: TControl;
begin
if FParentScreenshotBitmap.Canvas.BeginScene then
try
FDisablePaint := True;
if Parent is TCommonCustomForm then
begin
Form := Parent as TCommonCustomForm;
for Child in Form.Children do
if (Child is TControl) and (Child as TControl).Visible then
begin
ParentControl := Child as TControl;
ParentControl.PaintTo(FParentScreenshotBitmap.Canvas, ParentControl.ParentedRect);
end;
end
else
(Parent as TControl).PaintTo(FParentScreenshotBitmap.Canvas, RectF(0, 0, ParentWidth, ParentHeight));
finally
FDisablePaint := False;
FParentScreenshotBitmap.Canvas.EndScene;
end;
end;
begin
DefineParentSize;
if IsBitmapSizeChanged(FParentScreenshotBitmap, ParentWidth, ParentHeight) then
FParentScreenshotBitmap.SetSize(Round(ParentWidth), Round(ParentHeight));
MakeParentScreenshot;
Canvas.BeginScene;
try
FBlur.ProcessEffect(Canvas, FParentScreenshotBitmap, FBlur.Softness);
Canvas.DrawBitmap(FParentScreenshotBitmap, ParentedRect, LocalRect, 1, TRUE);
finally
Canvas.EndScene;
end;
end;
使用时,只需在任何控件上方实例化TGlass,它应该会产生您想要的“玻璃”效果。