{
* This Source Code Form is subject to the terms of the Mozilla Public License,
* v. 2.0. If a copy of the MPL was not distributed with this file, You can
* obtain one at http://mozilla.org/MPL/2.0/
*
* Copyright (C) 2007-2013, Peter Johnson (www.delphidabbler.com).
*
* $Rev$
* $Date$
*
* Implements class that manages display of status information and hints in a
* status bar.
}
unit UStatusBarMgr;
interface
uses
// Delphi
Windows, Graphics, ComCtrls;
type
{
TStatusBarMgr:
Class that manages display of status information and hints in a status bar.
}
TStatusBarMgr = class(TObject)
strict private
var
fStatusBar: TStatusBar;
{Reference to managed status bar}
fSearchGlyph: TBitmap;
{Stores reference to glyph used to indicate kind of latest search}
fModifiedGlyph: TBitmap;
{Stores glyph displayed when user database has been modified}
fSearchInfoVisible: Boolean;
{Flag noting whether search information is to be displayed or not}
fUserDBInfoVisible: Boolean;
{Flag noting whether user database modification indicator is displayed}
const
cDBPanel = 0; // index of database info panel
cSearchPanel = 1; // index of search info panel
cUserPanel = 2; // index of user-defined database info panel
cSimplePanel = cDBPanel; // index of simple message panel
procedure DrawPanel(StatusBar: TStatusBar; Panel: TStatusPanel;
const Rect: TRect);
{Handles status bar's OnDrawPanel event called whenever an owner-draw
status panel needs to be displayed.
@param StatusBar [in] Reference to status bar containing panel.
@param Panel [in] Reference to status bar panel to be drawn.
@param Rect [in] Bounding rectangle of panel relative to status bar.
}
procedure ShowSnippetsInfo;
{Displays snippets statistics in status bar.
}
procedure ShowSearchInfo;
{Causes information about a search to be displayed in status bar.
}
procedure HideSearchInfo;
{Prevents search information from being displayed in status bar.
}
procedure ShowUserDBInfo;
{Displays information about state of user defined database.
}
procedure HideUserDBInfo;
{Prevents user defined database information from being displayed in status
bar.
}
public
constructor Create(const SB: TStatusBar);
{Class constructor. Sets up object to manage a status bar.
@param SB [in] Status bar to be managed.
}
destructor Destroy; override;
{Class destructor. Tears down object.
}
procedure ShowHint(const Hint: string);
{Displays a hint in status bar or clears hint text if no hint is provided.
@param Hint [in] Hint to be displayed or '' to restore previous message.
}
procedure ShowSimpleMessage(const Msg: string);
{Displays a simple text message in first panel of status bar and hides
results displayed in other panels.
@param Msg [in] Message to be displayed.
}
procedure Update;
{Updates status bar and refreshes information displayed.
}
end;
implementation
{
NOTES
------------------------------------------------------------------------------
Status bar has three panels (indexed 0..2) used as follows:
+ Panel[0]: Displays database statistics: total number of snippets in each
database.
+ Panel[1]: Displays information about latest search. A glyph indicating
search type is displayed.
+ Panel[2]: Displays a modification flag and glyph if user defined database
has been modified since last save. Nothing is displayed when database is
not modified.
The status bar is also used to display hints when the mouse passes over
various UI elements. This is done by switching the status bar into SimplePanel
mode and displaying the hint in the single panel. Once the hint is deactivated
the main display is restored by switching the status bar out of SimplePanel
mode.
}
uses
// Delphi
SysUtils, Forms,
// Project
DB.UMain, UQuery, USearch, UStructs;
{ TStatusBarMgr }
constructor TStatusBarMgr.Create(const SB: TStatusBar);
{Class constructor. Sets up object to manage a status bar.
@param SB [in] Status bar to be managed.
}
resourcestring
// Message displayed when user database has been modified
sModified = 'Modified';
begin
Assert(Assigned(SB), ClassName + '.Create: SB is nil');
inherited Create;
fSearchInfoVisible := False; // we don't display search info by default
fUserDBInfoVisible := False; // we don't display modified flag by default
fSearchGlyph := TBitmap.Create;
fModifiedGlyph := TBitmap.Create;
fModifiedGlyph.LoadFromResourceName(HInstance, 'MODIFIED');
// Record reference to status bar
fStatusBar := SB;
// Ensure auto-hinting is switched off
fStatusBar.AutoHint := False;
// Enable owner drawing for second panel in status bar
fStatusBar.OnDrawPanel := DrawPanel;
fStatusBar.Panels[cDBPanel].Style := psOwnerDraw;
fStatusBar.Panels[cSearchPanel].Style := psOwnerDraw;
fStatusBar.Panels[cUserPanel].Style := psOwnerDraw;
fStatusBar.Panels[cUserPanel].Text := sModified;
end;
destructor TStatusBarMgr.Destroy;
{Class destructor. Tears down object.
}
begin
FreeAndNil(fModifiedGlyph);
FreeAndNil(fSearchGlyph);
inherited;
end;
procedure TStatusBarMgr.DrawPanel(StatusBar: TStatusBar;
Panel: TStatusPanel; const Rect: TRect);
{Handles status bar's OnDrawPanel event called whenever an owner-draw status
panel needs to be displayed.
@param StatusBar [in] Reference to status bar containing panel.
@param Panel [in] Reference to status bar panel to be drawn.
@param Rect [in] Bounding rectangle of panel relative to status bar.
}
procedure DrawGlyphInPanel(const Glyph: TBitmap; const Transparent: TColor);
{Draws a glyph at the left of a status bar panel, centred vertically.
@param Glyph [in] Glyph to be displayed.
@param Transparent [in] Colour key to be drawn transparently.
}
var
BoundsRect: TRectEx; // Bounding rectangle of panel
DestRect: TRect; // Rectangle in panel where glyph is drawn
SrcRect: TRect; // Bounding rectangle of glyph
begin
BoundsRect := Rect;
DestRect := TRectEx.CreateBounds(
BoundsRect.Left + 2,
BoundsRect.Top + (BoundsRect.Height - Glyph.Height) div 2,
Glyph.Width,
Glyph.Height
);
SrcRect := TRectEx.CreateBounds(0, 0, Glyph.Width, Glyph.Height);
StatusBar.Canvas.BrushCopy(DestRect, Glyph, SrcRect, Transparent);
end;
procedure DrawTextInPanel(const LeftMargin, RightMargin: Integer;
Text: string);
{Draws left aligned text in current status panel.
@param LeftMargin [in] Offset of text from left of panel.
@param RightMargin [in] Defines right hand edge of test in panel. Text is
clipped and an ellipsis drawn if it overflows this margin.
@param Text [in] Text to be displayed.
}
var
BoundsRect: TRectEx; // bounding rectangle of panel
TextRect: TRect; // rectangle in which to display text
TextH: Integer; // height of text
begin
BoundsRect := Rect;
TextH := StatusBar.Canvas.TextHeight(Text);
// need this rect calculation since vertical align flag to Canvas.TextRect
// doesn't work so we need to set top of text rect to required value
TextRect := TRectEx.Create(
BoundsRect.Left + LeftMargin,
BoundsRect.Top + (BoundsRect.Height - TextH) div 2,
BoundsRect.Right - RightMargin,
Rect.Bottom
);
StatusBar.Canvas.TextRect(
TextRect, Text, [tfLeft, tfTop, tfEndEllipsis]
);
end;
begin
// Clear the panel
StatusBar.Canvas.FillRect(Rect);
case Panel.ID of
cDBPanel:
DrawTextInPanel(2, 2, Panel.Text);
cSearchPanel:
begin
// We do nothing else if there's no glyph or search info not to be shown
if not Assigned(fSearchGlyph) or not fSearchInfoVisible then
Exit;
DrawGlyphInPanel(fSearchGlyph, clFuchsia);
DrawTextInPanel(fSearchGlyph.Width + 6, 0, Panel.Text);
end;
cUserPanel:
begin
// We do nothing else if there's no glyph or user db info not to be shown
if not Assigned(fModifiedGlyph) or not fUserDBInfoVisible then
Exit;
DrawGlyphInPanel(fModifiedGlyph, clWhite);
DrawTextInPanel(fModifiedGlyph.Width + 6, 12, Panel.Text);
end;
end;
end;
procedure TStatusBarMgr.HideSearchInfo;
{Prevents search information from being displayed in status bar.
}
begin
// This method does not directly hide the information, but flags that it
// should be hidden then causes the status bar to update itself using stored
// data. The DrawPanel method is called by the status bar to draw the required
// panel.
fSearchInfoVisible := False;
fStatusBar.Repaint;
end;
procedure TStatusBarMgr.HideUserDBInfo;
{Prevents user defined database information from being displayed in status
bar.
}
begin
// This method does not directly hide the information, but flags that it
// should be hidden then causes the status bar to update itself using stored
// data. The DrawPanel method is called by the status bar to draw the required
// panel.
fUserDBInfoVisible := False;
fStatusBar.Repaint;
end;
procedure TStatusBarMgr.ShowHint(const Hint: string);
{Displays a hint in status bar and restores previous message if no hint is
provided.
@param Hint [in] Hint to be displayed or '' to restore previous message.
}
begin
if Hint <> '' then
begin
// We have hint: hide status bar info and display hint
// we use simple panel to display hint in whole of status bar
fStatusBar.SimplePanel := True;
fStatusBar.SimpleText := Hint;
end
else
begin
// No hint: we restore normal status bar info by switching off simple panel
fStatusBar.SimplePanel := False;
fStatusBar.SimpleText := '';
end;
// Force status bar to repaint immediately
Application.ProcessMessages;
end;
procedure TStatusBarMgr.ShowSearchInfo;
{Causes information about a search to be displayed in status bar.
}
resourcestring
// Text displayed in search panel
sNoSearch = 'All snippets selected';
sSearchActiveS = '%d snippet selected';
sSearchActiveP = '%d snippets selected';
const
SearchActiveStr: array[Boolean] of string = (sSearchActiveS, sSearchActiveP);
var
SelectionCount: Integer; // Number of snippets selected in query
begin
// This method does not directly display the information, but records it and
// causes the status bar to update itself using the stored data. The DrawPanel
// method is called by the status bar to draw the panel.
// Store text describing search result
if Query.LatestSearch.Filter.IsNull then
fStatusBar.Panels[cSearchPanel].Text := sNoSearch
else
begin
SelectionCount := Query.Selection.Count;
fStatusBar.Panels[cSearchPanel].Text
:= Format(SearchActiveStr[SelectionCount <> 1], [Query.Selection.Count]);
end;
// Store glyph that indicates latest search type
fSearchGlyph.Assign((Query.LatestSearch.Filter as ISearchUIInfo).Glyph);
// Ensure search info panel of status bar is displayed
fSearchInfoVisible := True;
// Force status bar to repaint itself
fStatusBar.Repaint;
end;
procedure TStatusBarMgr.ShowSimpleMessage(const Msg: string);
{Displays a simple text message in first panel of status bar and hides results
displayed in other panels.
@param Msg [in] Message to be displayed.
}
begin
// Set first panel of status bar to message and force repaint
fStatusBar.Panels[cSimplePanel].Text := Msg;
Application.ProcessMessages;
// Hide any info displayed in other panels
HideSearchInfo;
HideUserDBInfo;
end;
procedure TStatusBarMgr.ShowSnippetsInfo;
{Displays snippets statistics in status bar.
}
var
TotalSnippets: Integer; // number of snippets in database
TotalUserSnippets: Integer; // number of snippets in user database
TotalMainSnippets: Integer; // number of snippets in main database
resourcestring
// status bar message strings
sSnippet = 'snippet';
sSnippets = 'snippets';
sStats = '%0:d %1:s (%2:d main / %3:d user defined)';
const
SnippetsStr: array[Boolean] of string = (sSnippet, sSnippets);
begin
// Calculate database stats
TotalSnippets := Database.Snippets.Count;
TotalUserSnippets := Database.Snippets.Count(True);
TotalMainSnippets := TotalSnippets - TotalUserSnippets;
// Build display text and display it
fStatusBar.Panels[cDBPanel].Text := Format(
sStats,
[
TotalSnippets,
SnippetsStr[TotalSnippets <> 1],
TotalMainSnippets,
TotalUserSnippets
]
);
end;
procedure TStatusBarMgr.ShowUserDBInfo;
{Displays information about state of user defined database.
}
begin
// This method does not directly display the information, but records whether
// panel needs to be drawn or hidden. The DrawPanel method is called by the
// status bar to draw the panel.
// We hide message if database not updated
fUserDBInfoVisible := (Database as IDatabaseEdit).Updated;
fStatusBar.Repaint;
end;
procedure TStatusBarMgr.Update;
{Updates status bar and refreshes information displayed.
}
begin
ShowSnippetsInfo;
ShowUserDBInfo;
ShowSearchInfo;
end;
end.
