The style selection mechanism in My Visual Database applications is like buying a pig in a poke* : it is impossible to imagine what the program will look like with the selected style until a reboot. A few lines of code will help us solve this problem.
* in Russian: купить кота в мешке
Solution
Unfortunately, you won’t be able to programmatically render the style, but you can prepare images in advance that will show the key elements of the interface using the selected style and display them in sync with the list of styles.
Pictures can be placed in the same folder as the style files, with names that match the names of the styles themselves. You also need to add another picture, which will show the program without applying the style (by default).
Scripts
const
STYLE_VIEWRE_FORM = 'frmStyleViewer';
procedure Style_StyleViewer;
// display view form and style selection
var
tmpForm: TForm;
tmpList: TListBox;
tmpImage: TImage;
tmpPanel: TPanel;
tmpButton: TdbButton;
i: integer;
begin
tmpForm := GetFormByName(STYLE_VIEWRE_FORM);
if tmpForm = nil then
begin
tmpForm := TForm.Create(Application);
with tmpForm do
begin
Name := STYLE_VIEWRE_FORM;
Caption := R('STYLE_VIEWRE_FORM_CAPTION',STYLE_VIEWRE_FORM_CAPTION);
Width := STYLE_VIEWRE_FORM_WIDTH;
Height := STYLE_VIEWRE_FORM_HEIGHT;
Position := poScreenCenter;
Scaled := False;
BorderStyle := bsSingle;
BorderIcons := biSystemMenu;
onShow := 'Style_StyleViewer_OnShow';
end;
// bottom of form
tmpPanel := TPanel.Create(tmpForm);
with tmpPanel do
begin
Parent := tmpForm;
Color := clGray;
Height := 44;
BorderWidth := 0;
Align := alBottom;
end;
tmpButton := TdbButton.Create(tmpForm);
AssignEvents(tmpButton);
with tmpButton do
begin
Parent := tmpPanel;
Name := 'btnCancel';
Font.Name := 'Segoe UI';
Font.Size := 11;
Caption := R('BUTTON_CAPTION_CANCEL',BUTTON_CAPTION_CANCEL);
dbActionType := adbCloseForm;
Height := 36;
Width := 109;
Left := tmpPanel.Width - Width - 4;
Top := 4;
Anchors := akRight + akTop;
Cancel := True;
Default := False;
end;
Button_SetImage(tmpButton);
//
tmpButton := TdbButton.Create(tmpForm);
AssignEvents(tmpButton);
with tmpButton do
begin
Parent := tmpPanel;
Name := 'btnSave';
Font.Name := 'Segoe UI';
Font.Size := 11;
Caption := R('BUTTON_CAPTION_SAVE',BUTTON_CAPTION_SAVE);
Height := 36;
Width := 119;
dbActionType := adbCloseForm;
OnClick := 'Style_StyleViewer_btnSave_OnClick';
Left := tmpPanel.Width - Width - 4 - 109 - 4;
Top := 4;
Anchors := akRight + akTop;
Cancel := False;
Default := True;
end;
Button_SetImage(tmpButton);
// main body of the form
tmpPanel := TPanel.Create(tmpForm);
with tmpPanel do
begin
Parent := tmpForm;
BorderWidth := 0;
Align := alClient;
end;
tmpList := TListBox.Create(tmpForm);
with tmpList do
begin
Name := 'lstStyles';
Font.Name := 'Segoe UI';
Font.Size := 11;
Parent := tmpPanel;
Width := 200;
Align := alLeft;
for i := 0 to Length(arStyles) - 1 do
begin
Items.add( arStyles[i] );
end;
OnClick := 'Style_StyleViewer_ListOnClick';
end;
tmpImage := TImage.Create( tmpForm );
with tmpImage do
begin
Parent := tmpPanel;
Name := 'imgPreview';
Align := alClient;
// Stretch := True;
Proportional := True;
Center := True;
end;
end;
FindC(tmpForm,'lstStyles',tmpList);
for i:=0 to tmpList.Items.Count - 1 do
begin
if tmpList.Items.Strings[ i ] = currentStyleName then
begin
tmpList.ItemIndex := i;
Style_StyleViewer_ListOnClick(tmpList); // upload picture
break;
end
end;
tmpForm.ShowModal;
end;
Code language: Delphi (delphi)The Style_StyleViewer() procedure is used to display the view form and select a style. This form looks like an editing form: at the bottom there is a panel with the “Save” and “Cancel” buttons, on the left – a list of styles, and in the middle – an image of the program with the selected style.
const
STYLE_PREVIEW_EXT = '.png';
procedure Style_StyleViewer_ListOnClick(Sender: TObject);
// click or select list item with keyboard arrows
var
tmpList: TListBox;
tmpFileName: string;
tmpStyleName: string;
tmpForm: TForm;
tmpImage: TImage;
begin
CForm(Sender,tmpForm);
tmpList := TListBox(Sender);
tmpStyleName := tmpList.Items.Strings[ tmpList.ItemIndex ];
tmpFileName := ExtractFilePath(Application.ExeName) + STYLE_DIR + tmpStyleName + STYLE_PREVIEW_EXT;
FindC(tmpForm,'imgPreview',tmpImage);
if not FileExists(tmpFileName) then
tmpFileName := ExtractFilePath(Application.ExeName) + STYLE_DIR + 'default' + STYLE_PREVIEW_EXT;
//
tmpImage.Picture.LoadFromFile(tmpFileName);
end;
Code language: Delphi (delphi)When a style is selected from the list, the Style_StyleViewer_ListOnClick() procedure finds the corresponding image and loads it for viewing. If the image is not found (which is quite expected for the first item in the list of styles), then the name of the image is changed to default.png
procedure Style_StyleViewer_btnSave_OnClick(Sender: TObject; var Cancel:boolean);
// saving and applying a style
var
tmpList: TListBox;
tmpStyleName: string;
tmpForm: TForm;
begin
CForm(Sender,tmpForm);
FindC(tmpForm,'lstStyles',tmpList);
tmpStyleName := tmpList.Items.Strings[ tmpList.ItemIndex ];
Style_SetStyle(tmpStyleName);
end;
Code language: Delphi (delphi)When you click the “Save” button, the style is applied by calling the Style_SetStyle() procedure.
Other improvements
- Style_StyleViewer_OnShow() – display style view form, list focus
- Resource_CreateMenu() – added an option that by default creates a language selection item inside the “Options” menu item
- Style_AddToMenu() – Create a menu item for interactive style selection.
- Style_mniStyleViewer_OnClick() – menu item handler for calling the style selection form.
- Button_SetImage() – a simplified procedure for assigning an image to a button
- english.txt, russian.txt – new data added to resource localization files
- Added application icon ClassExplorer.ico, it is built into ClassExplorer_.exe, as the ClassExplorer.exe file will be overwritten each time the project is changed.