colorshow.cpp

是一个较好的缩放工具

// ColorShow.cpp : implementation file
//

#include "stdafx.h"
#include "resource.h"
#include "ColorShow.h"
#include "Picker.h"
#include "Shower.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

DECLARE_MESSAGE(UWM_POINT)
DECLARE_MESSAGE(UWM_PICKER)
/////////////////////////////////////////////////////////////////////////////
// CColorShow

CColorShow::CColorShow()
   {
    dx = 16;
    dy = 16;
    dropper = ::LoadCursor(AfxGetInstanceHandle(), MAKEINTRESOURCE(IDC_PICKER));
    selection.SetRectEmpty();
   }

CColorShow::~CColorShow()
{
}


BEGIN_MESSAGE_MAP(CColorShow, CStatic)
        //{{AFX_MSG_MAP(CColorShow)
        ON_WM_LBUTTONDOWN()
        ON_WM_MOUSEMOVE()
        ON_WM_LBUTTONUP()
        ON_WM_PAINT()
        //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CColorShow message handlers

/****************************************************************************
*                            CColorShow::StartPick
* Inputs:
*       CPoint pt: Current point
* Result: void
*       
* Effect: 
*       Starts the pick operation. Initiates capture mode, changes the
*       cursor to the pickup cursor, and indicates by setting select to
*       FALSE that we are in pickup mode, not selection mode.
****************************************************************************/

void CColorShow::StartPick(CPoint pt)
    {
     SetCapture();
     ::SetCursor(dropper);
     select = FALSE;
    } // CColorShow::StartPick

/****************************************************************************
*                          CColorShow::OnLButtonDown
* Inputs:
*       UINT nFlags:
*       CPoint point:
* Result: void
*       
* Effect: 
*       Starts a selection operation. Sets capture mode and indicates that
*       the mode is "select" mode, which influences how mouse-moves are handled
****************************************************************************/

void CColorShow::OnLButtonDown(UINT nFlags, CPoint point) 
   {
    SetCapture();
    CRect r;
    GetClientRect(&r);
    previous = anchor = point;
    select = TRUE;
        
    CStatic::OnLButtonDown(nFlags, point);
   }

/****************************************************************************
*                          CColorShow::MakeSelection
* Result: CRect
*       A normalized rectangle for the current selection
****************************************************************************/

CRect CColorShow::MakeSelection()
    {
     CRect r;
     r.left = previous.x;
     r.top = previous.y;
     r.right = anchor.x;
     r.bottom = anchor.y;
     r.NormalizeRect();
     return r;
    } // CColorShow::MakeSelection

/****************************************************************************
*                          CColorShow::DrawSelection
* Inputs:
*       CDC & dc: DC to use
* Result: void
*       
* Effect: 
*       Draws a focus rectangle.
****************************************************************************/

void CColorShow::DrawSelection(CDC & dc)
    {
     CRect r = MakeSelection();
     dc.DrawFocusRect(&r);
    } // CColorShow::DrawSelection

/****************************************************************************
*                           CColorShow::OnMouseMove
* Inputs:
*       UINT nFlags: ignored
*       CPoint point: The point where the mouse is
* Result: void
*       
* Effect: 
*       The point is in client coordinates, but because we are in mouse
*       capture mode, these could well be outside the client area of the window.
*       If the mouse was clicked in the window, indicating a sub-selection is
*       being done, a selection rectangle is rubber-banded. If it is in
*       pickup mode, with the picker activated, the coordinates are converted
*       to screen coordinates and the image is recaptured.
****************************************************************************/

void CColorShow::OnMouseMove(UINT nFlags, CPoint point) 
   {
    if(GetCapture())
       { /* has capture */
        if(select)
           { /* selection */
            CClientDC dc(this);
            DrawSelection(dc);
            previous = point;
            DrawSelection(dc);
           } /* selection */
        else
           { /* pickup */
            where = point;
            ClientToScreen(&where);
            RecomputeImage();
           } /* pickup */
       } /* has capture */
    else
       { /* no capture */
        // Simply report the pixel under the point. This is the pixel
        // under the cursor as it moves in the exploded selection
        CClientDC sourceDC(this);
        color = sourceDC.GetPixel(point);
        GetParent()->SendMessage(UWM_POINT, 0, (LPARAM)color);
       } /* no capture */
        
    CStatic::OnMouseMove(nFlags, point);
   }

/****************************************************************************
*                           CColorShow::OnLButtonUp
* Inputs:
*       UINT nFlags: ignored
*       UINT CPoint: Point at which the button is release
* Result: void
*       
* Effect: 
*       If we are the dragging mode, releases capture. If it was an internal
*       selection, creates a logical selection rectangle which is later
*       converted to device space to do the drawing. If an external search,
*       notifies the parent window that dragging has ended.
****************************************************************************/

void CColorShow::OnLButtonUp(UINT nFlags, CPoint point) 
   {
    if(GetCapture() != NULL)
       { /* had capture */
        ReleaseCapture();
        if(select)
           { /* selection */
            CClientDC dc(this);
            DrawSelection(dc); // erase the selection
            CRect r = MakeSelection(); // create a selection rectangle
            selection = MapSelection(r);
            Invalidate();
           } /* selection */
        else
           { /* pickup */
            GetParent()->SendMessage(UWM_PICKER, (WPARAM)FALSE); // indicate release
            selection.SetRectEmpty();
           } /* pickup */
       } /* had capture */
    CStatic::OnLButtonUp(nFlags, point);
   }

/****************************************************************************
*                             CColorShow::GetSize
* Result: CSize
*       The size to use for computations
****************************************************************************/

CSize CColorShow::GetSize()
    {
     CRect r;
     GetClientRect(&r);
     CSize sz(r.Width() + 1, r.Height() + 1);
     return sz;
    } // CColorShow::GetSize

/****************************************************************************
*                            CColorShow::PrepareDC
* Inputs:
*       CDC & dc: DC to prepare
* Result: void
*       
* Effect: 
*       Sets the mapping mode
****************************************************************************/

void CColorShow::PrepareDC(CDC & dc)
    {
     CSize sz = GetSize();
     dc.SetMapMode(MM_ISOTROPIC);
     dc.SetWindowExt(dx, dy); // Note: Win32 Programming p. 267 says window-before-viewport
     dc.SetViewportExt(sz.cx, sz.cy);
    } // CColorShow::PrepareDC

/****************************************************************************
*                          CColorShow::MapSelection
* Inputs:
*       const CRect & r: Selection rectangle in exploded view
* Result: CRect
*       The representation as coordinates relative to the bitmap
****************************************************************************/

CRect CColorShow::MapSelection(const CRect & r)
    {
     CRect nr = r;
     CSize sz = GetSize();
     CClientDC dc(this);

     dc.SetMapMode(MM_ISOTROPIC);
     dc.SetWindowExt(dx, dy); // Note: Win32 Programming p. 267 says window-before-viewport
     dc.SetViewportExt(sz.cx, sz.cy);
     dc.DPtoLP(&nr);
     return nr; 
    } // CColorShow::MapSelection

/****************************************************************************
*                             CColorShow::OnPaint
* Result: void
*       
* Effect: 
*       Draws the image. This includes the centroid box during picking, and
*       the selection box after a selection has been made. Note the use of
*       scaling to convert between these coordinate systems.
****************************************************************************/

void CColorShow::OnPaint()