unit umain;

interface

uses
  Windows, Messages, SysUtils, {$IfNDef VER130} Variants, {$EndIf} Classes, Graphics, Controls, Forms,
  Dialogs, ieview, iemview, StdCtrls, FileCtrl, hyieutils, ExtCtrls, iexBitmaps, hyiedefs, iesettings, 
  iexLayers, iexRulers;

type
  TMainForm = class(TForm)
    GroupBox1: TPanel;
    DriveComboBox1: TDriveComboBox;
    DirectoryListBox1: TDirectoryListBox;
    ImageEnMView1: TImageEnMView;
    chkCustomDraw: TCheckBox;
    Label1: TLabel;
    procedure chkCustomDrawClick(Sender: TObject);
    procedure DirectoryListBox1Change(Sender: TObject);
    procedure ImageEnMView1ImageDraw2(Sender: TObject; idx, Left,
      Top: Integer; ImageRect: TRect; Canvas: TCanvas);
    procedure ImageEnMView1ImageAtPos(Sender: TObject; var idx: Integer; x,
      y: Integer);
    procedure ImageEnMView1CreateImage(Sender: TObject; idx: Integer);
    procedure ImageEnMView1DestroyImage(Sender: TObject; idx: Integer);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure ImageEnMView1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    { Private declarations }
  public
    { Public declarations }
    m_checkboxes : TList;
    FCheckBitmap : TBitmap;
    FNoCheckBitmap : TBitmap;
  end;

var
  MainForm: TMainForm;

implementation

{$ifNdef VER130}{$ifNdef VER140}  // From Delphi 7
uses
  uxTheme;
{$EndIf}{$EndIf}

{$R *.DFM}
{$R WindowsTheme.res}


// specify the checkbox relative position and size
const
  CHECK_LEFT = 4;
  CHECK_TOP  = 4;
  CHECK_WIDTH = 16;
  CHECK_HEIGHT = 16;


procedure DrawCheckBoxToBitmap(DestBitmap: TBitmap; bChecked: Boolean);
var        
{$ifNdef VER130}{$ifNdef VER140}  // From Delphi 7
  h: HTHEME;
{$EndIf}{$EndIf}
  r: TRect;
  s: TSize;
begin         
{$ifNdef VER130}{$ifNdef VER140}  // From Delphi 7
  if UseThemes then
  begin
    h := OpenThemeData(MainForm.Handle, 'BUTTON');
    if h <> 0 then
    try
      GetThemePartSize(h,
                       DestBitmap.Canvas.Handle,
                       BP_CHECKBOX,
                       CBS_CHECKEDNORMAL,
                       nil,
                       TS_DRAW,
                       s);

      DestBitmap.Width  := s.cx;
      DestBitmap.Height := s.cy;
      r := Rect(0, 0, s.cx, s.cy);

      if bChecked then        
        DrawThemeBackground(h,
                            DestBitmap.Canvas.Handle,
                            BP_CHECKBOX,
                            CBS_CHECKEDNORMAL,
                            r,
                            nil)
      else
        DrawThemeBackground(h,
                            DestBitmap.Canvas.Handle,
                            BP_CHECKBOX,
                            CBS_UNCHECKEDNORMAL,
                            r,
                            nil);
    finally
      CloseThemeData(h);
    end;
  end
  else  
{$EndIf}{$EndIf}
  begin       
    s.cx := GetSystemMetrics(SM_CXMENUCHECK);
    s.cy := GetSystemMetrics(SM_CYMENUCHECK);
    DestBitmap.Width  := s.cx;
    DestBitmap.Height := s.cy;
    r := Rect(0, 0, s.cx, s.cy);
    if bChecked then        
      DrawFrameControl(DestBitmap.Canvas.Handle,
                       r,
                       DFC_BUTTON,
                       DFCS_CHECKED)
    else
      DrawFrameControl(DestBitmap.Canvas.Handle,
                       r,
                       DFC_BUTTON,
                       DFCS_BUTTONCHECK);
  end;
end;

procedure TMainForm.chkCustomDrawClick(Sender: TObject);
begin
  ImageEnMView1.Invalidate;
end;


procedure TMainForm.FormCreate(Sender: TObject);
begin
  // m_checkboxes just contains "booleans". You could create a more complex object
  m_checkboxes := TList.Create;
                                     
  FCheckBitmap := TBitmap.Create;
  FNoCheckBitmap := TBitmap.Create;
  DrawCheckBoxToBitmap(FNoCheckBitmap, False);
  DrawCheckBoxToBitmap(FCheckBitmap, True);

  // load current directory
  DirectoryListBox1Change(self);
end;


procedure TMainForm.FormDestroy(Sender: TObject);
begin
  // remember to destroy also objects (if any)
  FreeAndNil(m_checkboxes);
  FCheckBitmap.free;
  FNoCheckBitmap.free;
end;


// load all images in the directory
procedure TMainForm.DirectoryListBox1Change(Sender: TObject);
begin
  ImageEnMView1.Clear;
  ImageEnMView1.FillFromDirectory(DirectoryListBox1.Directory);
  ImageEnMView1.SelectedImage := 0;
end;


// draws the checkbox
procedure TMainForm.ImageEnMView1ImageDraw2(Sender: TObject; idx, Left, Top: Integer; ImageRect: TRect; Canvas: TCanvas);
var
  x1, y1, x2, y2:integer;
begin
  x1 := Left + CHECK_LEFT;
  y1 := Top + CHECK_TOP;
  x2 := Left + CHECK_LEFT + CHECK_WIDTH;
  y2 := Top + CHECK_TOP + CHECK_HEIGHT;

  if chkCustomDraw.checked then
  begin   
    Canvas.Pen.Color := clBlack;
    Canvas.Pen.Width := 2;
    Canvas.Brush.Color := clLime;
    if boolean(m_checkboxes[idx]) then
    begin
      Canvas.Brush.Style := bsSolid;
      Canvas.Rectangle(x1, y1, x2+1, y2+1);
      Canvas.MoveTo(x1, y1); Canvas.LineTo(x2, y2);
      Canvas.MoveTo(x2, y1); Canvas.LineTo(x1, y2);
    end
    else
    begin
      Canvas.Brush.Style := bsClear;
      Canvas.Rectangle(x1, y1, x2, y2);
    end;
  end
  else
  begin     
    if boolean(m_checkboxes[idx]) then
      Canvas.Draw(x1, y1, FCheckBitmap)
    else
      Canvas.Draw(x1, y1, FNoCheckBitmap);
  end
end;


// check if inside the checkbox, avoid to select using the checkbox
procedure TMainForm.ImageEnMView1ImageAtPos(Sender: TObject; var idx: Integer; x, y: Integer);
begin
  if idx > -1 then
  begin
    // get relative mouse position (relative to the thumbnail)
    x := x + ImageEnMView1.ViewX - ImageEnMView1.ImageX[idx];
    y := y + ImageEnMView1.ViewY - ImageEnMView1.ImageY[idx];

    // is the point inside the checkbox?
    if IEPointInRect(x, y, CHECK_LEFT, CHECK_TOP, CHECK_LEFT + CHECK_WIDTH, CHECK_TOP + CHECK_HEIGHT) then
      idx := -1;  // no image is selected here
  end;
end;


// handle check/uncheck checkbox
procedure TMainForm.ImageEnMView1MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
var
  idx:integer;
  bClickedCheck: Boolean;
begin
  // which thumbnail is there at X,Y?
  idx := ImageEnMView1.ImageAtPos(X, Y);

  if idx > -1 then
  begin
    // get relative mouse position (relative to the thumbnail)
    x := x + ImageEnMView1.ViewX - ImageEnMView1.ImageX[idx];
    y := y + ImageEnMView1.ViewY - ImageEnMView1.ImageY[idx];
                              
    // is the point inside the checkbox?
    if chkCustomDraw.checked then
      bClickedCheck := IEPointInRect(x, y, CHECK_LEFT, CHECK_TOP, CHECK_LEFT + CHECK_WIDTH, CHECK_TOP + CHECK_HEIGHT)
    else
      bClickedCheck := IEPointInRect(x, y, CHECK_LEFT, CHECK_TOP, CHECK_LEFT + FCheckBitmap.Width, CHECK_TOP + FCheckBitmap.Height);

    if bClickedCheck then
    begin
      // yes, check/uncheck it
      m_checkboxes[idx] := pointer( not boolean(m_checkboxes[idx]) );
      // redraw the image (hence the method ImageEnMView1ImageDraw2 is called)
      ImageEnMView1.UpdateImage(idx);
    end;
  end;
end;


// a new image is inserted
procedure TMainForm.ImageEnMView1CreateImage(Sender: TObject; idx: Integer);
begin
  m_checkboxes.Insert(idx, pointer(false));
end;


// an image is removed
procedure TMainForm.ImageEnMView1DestroyImage(Sender: TObject; idx: Integer);
begin
  if assigned(m_checkboxes) then  
    m_checkboxes.Delete(idx);
end;



end.