An improvement on the CBitmapButton class.位图按钮类

// ImageButton.cpp : implementation file // #include "stdafx.h" #include "button.h" #include "ImageButton.h" #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ///////////////////////////////////////////////////////////////////////////// // CImageButton CImageButton::CImageButton(UINT up, UINT down, UINT disabled, BOOL fill) { this->up = up; this->down = down; this->disabled = disabled; this->m_fill = fill; } CImageButton::~CImageButton() { }  BEGIN_MESSAGE_MAP(CImageButton, CButton) //{{AFX_MSG_MAP(CImageButton) // NOTE - the ClassWizard will add and remove mapping macros here. //}}AFX_MSG_MAP END_MESSAGE_MAP() ///////////////////////////////////////////////////////////////////////////// // CImageButton message handlers  /**************************************************************************** * CImageButton::SetVPos * Inputs: * DWORD newstyle: Vertical style, one of BS_TOP, BS_BOTTOM, BS_VCENTER * Result: DWORD * Previous style * Effect: * Sets the style ****************************************************************************/ DWORD CImageButton::SetVPos(DWORD newstyle) { DWORD style = GetStyle(); DWORD result = style; style &= ~ (BS_TOP | BS_BOTTOM | BS_VCENTER); style |= newstyle; ::SetWindowLong(m_hWnd, GWL_STYLE, (long)style); InvalidateRect(NULL); return result & (BS_TOP | BS_BOTTOM | BS_VCENTER); } // CImageButton::SetVPos  /**************************************************************************** * CImageButton::SetHPos * Inputs: * DWORD newstyle: Horizontal style, one of BS_LEFT, BS_RIGHT, BS_CENTER * Result: DWORD * Previous style * Effect: * Sets the style ****************************************************************************/ DWORD CImageButton::SetHPos(DWORD newstyle) { DWORD style = GetStyle(); DWORD result = style; style &= ~ (BS_LEFT | BS_RIGHT | BS_CENTER); style |= newstyle; ::SetWindowLong(m_hWnd, GWL_STYLE, (long)style); InvalidateRect(NULL); return result & (BS_LEFT | BS_RIGHT | BS_CENTER); } // CImageButton::SetHPos  void CImageButton::DrawItem(LPDRAWITEMSTRUCT dis) { CDC * dc = CDC::FromHandle(dis->hDC); // Get a CDC we can use CRect r(dis->rcItem); // Copy the button rectangle HBITMAP bitmap; // Handle to the bitmap we are drawing BITMAP bmpval; // Parameters of the bitmap CPoint fpos(0,0); // Focus position CPoint ipos(0,0); // Image position CSize border(::GetSystemMetrics(SM_CXBORDER), ::GetSystemMetrics(SM_CYBORDER)); // Dimensions of a border line // We use ::GetSystemMetrics so we work on // hi-res displays CPoint baseOffset(border.cx, border.cy); // Offset amount if button-down int saved = dc->SaveDC(); // Save the DC for later restoration BOOL grayout = FALSE; // Gray out stock image? CPoint bltStart(0, 0); // Nominal start of BLT // The first thing we do is deflate our useful area by the width of a // frame, which is twice a border. r.InflateRect(-2 * border.cx, -2 * border.cy); // Load the bitmap. The three states are // ODS_SELECTED ODS_DISABLED // 1 n/a Button is pressed // 0 0 Button is up // 0 1 Button is disabled // // The possible images supplied The images used // ------specified------ ----------use---------- // up down disabled up down disabled // ===================== ======================== // A B C A B C // A 0 C A A C // A B 0 A B gray(A) // A 0 0 A A gray(A) UINT id = 0; if(dis->itemState & ODS_SELECTED) { /* selected */ // If the down image is given, use that, else use the // up image id = down != 0 ? down : up; } /* selected */ else { /* unselected */ if(dis->itemState & (ODS_DISABLED | ODS_GRAYED)) { /* grayed */ if(disabled == 0) { /* no disabled image */ id = up; grayout = TRUE; // gray out manually } /* no disabled image */ else { /* use disabled image */ id = disabled; } /* use disabled image */ } /* grayed */ else { /* enabled */ id = up; } /* enabled */ } /* unselected */ bitmap = (HBITMAP)::LoadImage(AfxGetInstanceHandle(), MAKEINTRESOURCE(id), IMAGE_BITMAP, 0, 0, LR_LOADMAP3DCOLORS); // Get the bitmap parameters, because we will need width and height ::GetObject(bitmap, sizeof(BITMAP), &bmpval); // We compute the desired image size. Because we could offset // the image on a button-down, we take that potential into // consideration so we don't truncate the image on the right // or bottom when we depress the button CSize image; // Compute the origin of the focus rectangle (fpos) and the // bitmap image (ipos) // If we are in fill mode, this computation is simple // otherwise, we have to take the various alignments into consideration if(!m_fill) { /* compute alignment */ // We need to compute the x,y horizontal coordinates // Compute the width and height of the available client area for later convenience // This just saves writing r.Width() and r.Height() all the time and // having the values recomputed CSize clientArea(r.Width(), r.Height()); DWORD style = GetStyle(); image.cx = bmpval.bmWidth; image.cy = bmpval.bmHeight; style &= (BS_LEFT | BS_RIGHT | BS_CENTER); switch(style) { /* hstyle */ case BS_LEFT: fpos.x = 2 * border.cx; ipos.x = fpos.x + border.cx; break; case BS_RIGHT: fpos.x = clientArea.cx - image.cx; if(fpos.x < 2 * border.cx) { /* adjust right */ bltStart.x = image.cx - clientArea.cx; fpos.x = 2 * border.cx; } /* adjust right */ ipos.x = fpos.x + border.cx; break; case 0: case BS_CENTER: fpos.x = (clientArea.cx - image.cx) / 2 + border.cx; if(fpos.x < 2 * border.cx) { /* adjust center */ bltStart.x = (image.cx - clientArea.cx) / 2; fpos.x = 2 * border.cx; } /* adjust center */ ipos.x = fpos.x + border.cx; break; } /* hstyle */ style = GetStyle(); style &= (BS_TOP | BS_BOTTOM | BS_VCENTER); switch(style) { /* vstyle */ case BS_TOP: fpos.y = 2 * border.cy; ipos.y = fpos.y + border.cy; break; case BS_BOTTOM: fpos.y = clientArea.cy - image.cy; if(fpos.y < 2 * border.cy) { /* adjust to bottom */ bltStart.y = image.cy - clientArea.cy; fpos.y = 2 * border.cy; } /* adjust to bottom */ ipos.y = fpos.y + border.cy; break; case 0: case BS_VCENTER: fpos.y = (clientArea.cy - image.cy) / 2 + border.cy; if(fpos.y < 2 * border.cy) { /* adjust top */ bltStart.y = (image.cy - clientArea.cy) / 2; fpos.y = 2 * border.cy; } /* adjust top */ ipos.y = fpos.y + border.cy; break; } /* vstyle */ } /* compute alignment */ else { /* fill alignment */ image.cx = r.Width() - baseOffset.x; image.cy = r.Height() - baseOffset.y; fpos.x = 2 * border.cx; ipos.x = fpos.x + border.cx; fpos.y = 2 * border.cy; ipos.y = fpos.y + border.cy; } /* fill alignment */ // Compute the focus rectangle area CRect focus(fpos.x, fpos.y, fpos.x + image.cx + 2 * border.cx, fpos.y + image.cy + 2 * border.cy); // For visual effect, if the button is down, shift the image over and // down to make it look "pushed". CPoint useOffset(0, 0); if(dis->itemState & ODS_SELECTED) { /* down */