How to let TVirtualStringTree to display an icon in disabled state?
I need to display files in a directory to a TVirtualStringTree.
So, I use SHGetFileInfo to get files' icons.
But seems I can only get "normal" icons (Left side on following screen shot).
If so, can TVirtualStringTree draw icons as "disabled"?
Just like you disabled the a node. Please see a screen shot:
UPDATED
There is a similar thread in Soft Gems forum.
I can get the rect of the icon then draw the icon myself.
I'm using TcxImageList and it can draw the "disabled" icon easily.
I firstly assigned a non-exist image index in GetImageIndex event
so I have a room to draw the icon. Then using following code to draw.
procedure TfrmMain.tvSharesAfterItemPaint(Sender: TBaseVirtualTree; TargetCanvas: TCanvas; Node: PVirtualNode; ItemRect: TRect);
var
rImage: TRect;
OffsetLeft: Integer;
begin
rImage := ItemRect; with TVirtualStringTree(Sender) do begin
if (toShowRoot in TreeOptions.PaintOptions) then
OffsetLeft := Indent * (GetNodeLevel(Node) + )
else
OffsetLeft := Indent * GetNodeLevel(Node); Inc(rImage.Left, Margin + OffsetLeft);
Inc(rImage.Top, (NodeHeight[Node] - Images.Height) div );
rImage.Right := rImage.Left + Images.Width;
rImage.Bottom := rImage.Top + Images.Height;
end; // draw the "normal" or "disabled" icon here
imageList.Draw(TargetCanvas, rImage.left, rImage.Top, ...);
end;
end;
No, TVirtualStringTree does not have an explicit DisabledIcon property or any thing similiar.
However, you can achieve your desired result by an appropriate handler for the GetImageIndex event.
In the event handler for this event, determine if the node is disabled or not,
and use this test as a discriminator for computing the image index.
In your imagelist, you will need to have normal versions of glyphs and disabled versions.
VirtualTree will not magically create the disabled versions for you,
however it is a trivial matter to clone a glyph and grey wash it.
Let me know if you need demo code, either for the GetImageIndex event handler, or for grey washing.
There's no direct way to draw disabled image state.
I would prefer to create the event for custom drawing of the images
(now I've suggested this as a new featurefor virtual tree view, due to this lack).
Here is the example with interposed class for virtual string tree.
For custom drawing of grayscale images, it uses the code from this post.
Surely, it's not a solution for permanent use, you would have to keep the PaintImage method code
synchronized with the actual code since the method is completely overriden.
Parameter count of the OnCustomDrawImage event points to that parameters deserve to wrap to some structure,
but it's just a showcase how would it look like.
This new event is fired twice;
first time for image draw (the DrawOverlay is False) and
second time for overlay (the DrawOverlay parameter is True):
unit Unit1; interface uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, DateUtils, StdCtrls, VirtualTrees, ImgList, CommCtrl; type
TCustomDrawImageEvent = procedure(Sender: TBaseVirtualTree; Node: PVirtualNode;
ImageList: TCustomImageList; ImageIndex: Integer; TargetCanvas: TCanvas;
X, Y: Integer; Style: Cardinal; DrawEnabled: Boolean; DrawOverlay: Boolean;
var CustomDraw: Boolean) of object;
TVirtualStringTree = class(VirtualTrees.TVirtualStringTree)
private
FOnCustomDrawImage: TCustomDrawImageEvent;
protected
function DoCustomDrawImage(Node: PVirtualNode; ImageList: TCustomImageList;
ImageIndex: Integer; TargetCanvas: TCanvas; X, Y: Integer; Style: Cardinal;
DrawEnabled: Boolean; DrawOverlay: Boolean): Boolean; virtual;
procedure PaintImage(var PaintInfo: TVTPaintInfo; ImageInfoIndex: TVTImageInfoIndex;
DoOverlay: Boolean); override;
published
property OnCustomDrawImage: TCustomDrawImageEvent read FOnCustomDrawImage write FOnCustomDrawImage;
end; type
TForm1 = class(TForm)
VirtualStringTree1: TVirtualStringTree;
ImageList1: TImageList;
procedure FormCreate(Sender: TObject);
procedure VirtualStringTree1GetImageIndex(Sender: TBaseVirtualTree;
Node: PVirtualNode; Kind: TVTImageKind; Column: TColumnIndex;
var Ghosted: Boolean; var ImageIndex: Integer);
private
procedure VirtualTreeCustomDrawImage(Sender: TBaseVirtualTree; Node: PVirtualNode;
ImageList: TCustomImageList; ImageIndex: Integer; TargetCanvas: TCanvas;
X, Y: Integer; Style: Cardinal; DrawEnabled: Boolean; DrawOverlay: Boolean;
var CustomDraw: Boolean);
public
{ Public declarations }
end; var
Form1: TForm1; implementation {$R *.dfm} { TVirtualStringTree } type
TCustomImageListCast = class(TCustomImageList); function TVirtualStringTree.DoCustomDrawImage(Node: PVirtualNode;
ImageList: TCustomImageList; ImageIndex: Integer; TargetCanvas: TCanvas; X,
Y: Integer; Style: Cardinal; DrawEnabled: Boolean; DrawOverlay: Boolean): Boolean;
begin
Result := False;
if Assigned(FOnCustomDrawImage) then
FOnCustomDrawImage(Self, Node, ImageList, ImageIndex, TargetCanvas, X, Y,
Style, DrawEnabled, DrawOverlay, Result);
end; procedure TVirtualStringTree.PaintImage(var PaintInfo: TVTPaintInfo;
ImageInfoIndex: TVTImageInfoIndex; DoOverlay: Boolean);
var
CutNode: Boolean;
ExtraStyle: Cardinal;
DrawEnabled: Boolean;
PaintFocused: Boolean;
const
Style: array[TImageType] of Cardinal = (, ILD_MASK);
begin
with PaintInfo do
begin
CutNode := (vsCutOrCopy in Node.States) and (tsCutPending in TreeStates);
PaintFocused := Focused or (toGhostedIfUnfocused in TreeOptions.PaintOptions);
if DoOverlay then
GetImageIndex(PaintInfo, ikOverlay, iiOverlay, Images)
else
PaintInfo.ImageInfo[iiOverlay].Index := -;
DrawEnabled := not (vsDisabled in Node.States) and Enabled;
with ImageInfo[ImageInfoIndex] do
begin
if (vsSelected in Node.States) and not (Ghosted or CutNode) then
begin
if PaintFocused or (toPopupMode in TreeOptions.PaintOptions) then
Images.BlendColor := Colors.FocusedSelectionColor
else
Images.BlendColor := Colors.UnfocusedSelectionColor;
end
else
Images.BlendColor := Color;
if (ImageInfo[iiOverlay].Index > -) and (ImageInfo[iiOverlay].Index < ) then
ExtraStyle := ILD_TRANSPARENT or ILD_OVERLAYMASK and
IndexToOverlayMask(ImageInfo[iiOverlay].Index + )
else
ExtraStyle := ILD_TRANSPARENT;
if (toUseBlendedImages in TreeOptions.PaintOptions) and PaintFocused
and (Ghosted or ((vsSelected in Node.States) and
not (toFullRowSelect in TreeOptions.SelectionOptions) and
not (toGridExtensions in TreeOptions.MiscOptions)) or CutNode)
then
ExtraStyle := ExtraStyle or ILD_BLEND50;
if (vsSelected in Node.States) and not Ghosted then
Images.BlendColor := clDefault; // in this modified part of code, the new event OnCustomDrawImage
// is fired once before the image is actually drawn and once when
// the overlay is to be drawn; when you keep its CustomDraw param
// in False value (what is, by default), the default drawing will
// be done otherwise you need to take care of drawing by yourself // draw image default way when the CustomDraw parameter of the new
// OnCustomDrawImage event remains False (what is, by default)
if not DoCustomDrawImage(Node, Images, Index, Canvas, XPos, YPos,
Style[Images.ImageType] or ExtraStyle, DrawEnabled, False)
then
TCustomImageListCast(Images).DoDraw(Index, Canvas, XPos, YPos,
Style[Images.ImageType] or ExtraStyle, DrawEnabled);
// draw overlay default way when the CustomDraw parameter of the new
// OnCustomDrawImage event remains False (what is, by default)
if PaintInfo.ImageInfo[iiOverlay].Index >= then
begin
if not DoCustomDrawImage(Node, ImageInfo[iiOverlay].Images,
ImageInfo[iiOverlay].Index, Canvas, XPos, YPos,
Style[ImageInfo[iiOverlay].Images.ImageType] or ExtraStyle,
DrawEnabled, True)
then
TCustomImageListCast(ImageInfo[iiOverlay].Images).DoDraw(
ImageInfo[iiOverlay].Index, Canvas, XPos, YPos,
Style[ImageInfo[iiOverlay].Images.ImageType] or ExtraStyle,
DrawEnabled);
end;
end;
end;
end; { TForm1 } procedure TForm1.FormCreate(Sender: TObject);
begin
VirtualStringTree1.OnCustomDrawImage := VirtualTreeCustomDrawImage;
end; type
TImageListDrawParams = record
cbSize: DWORD;
himl: HIMAGELIST;
i: Integer;
hdcDst: HDC;
x: Integer;
y: Integer;
cx: Integer;
cy: Integer;
xBitmap: Integer;
yBitmap: Integer;
rgbBk: COLORREF;
rgbFg: COLORREF;
fStyle: UINT;
dwRop: DWORD;
fState: DWORD;
Frame: DWORD;
crEffect: COLORREF;
end; procedure DrawDisabledImage(DC: HDC; ImageList: TCustomImageList; Index, X,
Y: Integer);
var
Options: TImageListDrawParams;
begin
FillChar(Options, SizeOf(Options), );
Options.cbSize := SizeOf(Options);
Options.himl := ImageList.Handle;
Options.i := Index;
Options.hdcDst := DC;
Options.x := X;
Options.y := Y;
Options.fState := ILS_SATURATE;
ImageList_DrawIndirect(@Options);
end; procedure TForm1.VirtualStringTree1GetImageIndex(Sender: TBaseVirtualTree;
Node: PVirtualNode; Kind: TVTImageKind; Column: TColumnIndex;
var Ghosted: Boolean; var ImageIndex: Integer);
begin
ImageIndex := ;
end; procedure TForm1.VirtualTreeCustomDrawImage(Sender: TBaseVirtualTree;
Node: PVirtualNode; ImageList: TCustomImageList; ImageIndex: Integer;
TargetCanvas: TCanvas; X, Y: Integer; Style: Cardinal; DrawEnabled: Boolean;
DrawOverlay: Boolean; var CustomDraw: Boolean);
begin
CustomDraw := True;
if not DrawOverlay then
DrawDisabledImage(TargetCanvas.Handle, ImageList, ImageIndex, X, Y);
end; end.
And the result (I have to say it would be fine to blend it yet):