[yunqa.de] Re: Suggestion - Make TDiHtmlLabel.FRect protected.
- From: Edwin Yip <edwin.yip@xxxxxxxxxxxxxxxxxx>
- To: yunqa@xxxxxxxxxxxxx
- Date: Wed, 22 Feb 2012 01:41:18 +0800
Hi Ralf,
Well, by creating an decedent component I don't have to write the
OnMouseEnter/Leave event handlers - this is the only benefit and I believe
it's the benefit of OOP.
Below is my derived component, I added two properties:
HotColor
Hot.
Source:
unit MyHtmlLabel;
interface
uses
SysUtils, Classes, Controls, DIHtmlLabel, Messages, Graphics, Math;
type
TMyHtmlLabel = class(TDIHtmlLabel)
strict private
FHot: Boolean;
FHotColor: TColor;
procedure SetHot(const Value: Boolean);
procedure SetHotColor(const Value: TColor);
private
procedure CMMouseEnter(var Msg: TMessage); message CM_MOUSEENTER;
procedure CMMouseLeave(var Msg: TMessage); message CM_MOUSELEAVE;
{ Private declarations }
protected
procedure Paint; override;
public
constructor Create(AOwner: TComponent);
published
property Hot: Boolean read FHot write SetHot default False;
property HotColor: TColor read FHotColor write SetHotColor default
clSkyBlue;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('Edwin', [TMyHtmlLabel]);
end;
constructor TMyHtmlLabel.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
HotColor := $00FFF2F2;
end;
procedure TMyHtmlLabel.CMMouseEnter(var Msg: TMessage);
begin
inherited;
Hot := True;
// if Assigned(FOnMouseEnter) then
// FOnMouseEnter(self);
end;
procedure TMyHtmlLabel.CMMouseLeave(var Msg: TMessage);
begin
inherited;
Hot := False;
// if Assigned(FOnMouseLeave) then
// FOnMouseLeave(self);
end;
procedure TMyHtmlLabel.Paint;
begin
// no calling inherited here. the following code is modified based on
TDiHtmlLabel.Paint.
if Assigned(FNodeTree) then
begin
with Canvas do
begin
if Hot then
begin
Brush.Color := Self.HotColor;
Brush.Style := bsSolid;
FillRect(ClientRect);
end
else if not Transparent then
begin
Brush.Color := Self.Color;
Brush.Style := bsSolid;
FillRect(ClientRect);
end
else
Brush.Style := bsClear;
end;
Canvas.Font := Font;
Renderer.RenderTree(Canvas, FRect, FNodeTree);
if AutoHeight and (Align in [alNone, alTop, alBottom]) then
ClientHeight := Renderer.TextHeight + MarginHeight;
end;
if Assigned(OnAfterPaint) then
OnAfterPaint(Self);
end;
procedure TMyHtmlLabel.SetHot(const Value: Boolean);
begin
if FHot <> Value then
begin
FHot := Value;
Invalidate;
end;
end;
procedure TMyHtmlLabel.SetHotColor(const Value: TColor);
begin
if FHotColor <> Value then
begin
FHotColor := Value;
end;
end;
end.
On Mon, Feb 20, 2012 at 7:01 AM, Delphi Inspiration <delphi@xxxxxxxx> wrote:
> On 19.02.2012 14:56, Edwin Yip wrote:
>
> > Yes, when drawing the background to indicate the 'hot' status of the
> > label, I use ClientRect, but since in my overridden Paint() method I
> > can't call inherited, instead I have to copy and modify the method body
> > of TDiHtmlLabel which needs to access the FRect field in order to paint
> > the html tags.
> >
> > Precisely, it's the following code:
> > Renderer.RenderTree(Canvas, FRect, FNodeTree);
>
> I still do not understand why you want to go the extra way. Attached is
> a project which demonstrates my concept. The archive also contains the
> updated DIHtmlLabel.pas unit which you must install into the Delphi IDE
> to open the form in design-view. A simple compile should work without
> installation.
>
> If your solution has benefits over my approach, I'd be interested if you
> could share your code.
>
> Ralf
>
--
Best Regards,
Edwin Yip
Mind Mapping is as Effortless as Typing
http://www.InnovationGear.com
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