请教问题一,如何在画的过程中有虚框

[lingdang]

我照着书上的例子依胡芦画票写了个画矩型的程序,程序大至如下

void CTestView::OnLButtonDown(UINT nFlags, CPoint point)
{
....
m_LastPoint=point;
CView::OnLButtonDown(nFlags, point);
...
}

void CTestView::OnLButtonUp(UINT nFlags, CPoint point)
{
.....
dc.Rectangle(m_LastPoint.x,m_LastPoint.y,m_CurPoint.x,m_CurPoint.y);
....
}
编译成功后,可以通过,也可以画矩型,问题是,我想和WINDOWS画笔那
样,在画的过程中有虚框,(就象拖动窗口的那样)这样可以知道矩型框
的大小,不知道怎么样添代码??(我是新手,麻烦您老人家告诉我的时
候说的尽量详细一点,拜托了)

[xenogear]

在OnMouseMove中处理贝

[929]

这种用鼠标拖动来画矩形，一般在MOUSEDOWN下记住原鼠标点位置，在MOUSEMOVE事件中，以XOR异或的方式进行画矩形的操作，并且更新原鼠标位置值。这样，可以保证画出的矩形可被移动后的重画所清除。在一般的VC或其它编程书中介绍绘图功能时都有这样的示例。看看吧。

[JJONY]

你是不是想在View中先画一个虚的矩形,当Kick up时就出现一个矩形?
介绍你用一个类---CRectTracker,该类不难.
在void CTestView::OnLButtonDown(UINT nFlags, CPoint point) 中
加入如下:
CRectTracker track;
CRect rc;
track.TrackRubberBand(this,point);
rc = track.m_rect
.....余下操作

[lingdang]

jjony:
谢谢你，我已按照你所说的

void CCcyView::OnLButtonDown(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default

CClientDC dc(this);
m_LastPoint=point;
CRectTracker track;
CRect rc;
track.TrackRubberBand(this,point);
rc = track.m_rect;
dc.Rectangle(rc);
... ...

试验成功了，但是track.TrackRubberBand(this,point);
这个好象会屏蔽OnLButtonUp
是不是在OnLButtonDown语句中加了就不能用
OnLButtonUp了？

xenogear：
谢谢！
你能不能说的详细一点？？？
不明白！

929：
我开始也象你那样想了，可是我很菜的，我不知道具体应该怎么做你能不能给我一
段代码加以说明，或者一小段也可以！我先谢谢了！

还有的等会再试！

[E]

void CTestView::OnLButtonDown(UINT nFlags, CPoint point)
{
....
m_LastPoint=point;
m_TrackPoint=point;
m_bLButtondown=TRUE;
CView::OnLButtonDown(nFlags, point);
...
}

void CTestView::OnLButtonUp(UINT nFlags, CPoint point)
{
.....
RECT rc;
m_bLButtonDown=FALSE;
set rc to be (m_LastPoint.x,m_LastPoint.y,m_TrackPoint.x,m_TrackPoint.y)
DrawFocusRect(dc.m_hdc,rc); //擦掉原先的FocusRect;
dc.Rectangle(m_LastPoint.x,m_LastPoint.y,point.x,point.y);
....
}

void CTestView::OnMouseMove(UINT nFlags, CPoint point)
{
.....
RECT rc;
if (m_bLButtondown){
set rc to be (m_LastPoint.x,m_LastPoint.y,m_TrackPoint.x,m_TrackPoint.y)
DrawFocusRect(dc.m_hdc,rc); //擦掉原先的FocusRect;
m_TrackPoint=point;
set rc to be (m_LastPoint.x,m_LastPoint.y,m_TrackPoint.x,m_TrackPoint.y)
DrawFocusRect(dc.m_hdc,rc); //画现在的FocusRect
}
....
}
不要给我分，我也是猜想而已，并没测试过！

[JJONY]

lingdang:还需要OnLButtonUp吗?track.TrackRubberBand()执行后，只有在释放鼠标左键后才返回，所以WM_LBUTTONUP消息就被track处理了,窗口自然就不会激发OnLButtonUP函数啦。你在track.TrackRubberBand后续代码操作吧。

[lingdang]

jjony
可是我并不想担担就画一个矩型，我还想用到MOUSEMOVE
所以。。。总之还是要谢谢你这么热　心！

SoftCrazy:
谢谢你的指点
我已经按你教我的思路成功完成代码
并测试成功，我觉你的比较好：代码如下：不过我的
代码可能写的很不精简！

CLASS CVIEW:....
....
protected:
CPoint m_LastPoint;
CPoint m_TrackPoint;
...........


void CRectangleView::OnLButtonUp(UINT nFlags, CPoint point)
{
CClientDC dc(this);
CRect rc;
int m_top,m_left,m_right,m_bottom;
if (m_LastPoint.x>m_TrackPoint.x)
{
m_left=m_TrackPoint.x;
m_right=m_LastPoint.x;
}
else
{
m_right=m_TrackPoint.x;
m_left=m_LastPoint.x;
}
if (m_LastPoint.y>m_TrackPoint.y)
{
m_top=m_TrackPoint.y;
m_bottom=m_LastPoint.y;
}
else
{
m_bottom=m_TrackPoint.y;
m_top=m_LastPoint.y;
}


rc.top=m_top;
rc.left=m_left;
rc.right=m_right;
rc.bottom=m_bottom;

DrawFocusRect(dc.m_hDC,rc);
Rectangle(dc,m_LastPoint.x,m_LastPoint.y,point.x,point.y);


CView::OnLButtonUp(nFlags, point);
}

void CRectangleView::OnLButtonDown(UINT nFlags, CPoint point)
{
m_LastPoint=point;
m_TrackPoint=point;
CView::OnLButtonDown(nFlags, point);
}

void CRectangleView::OnMouseMove(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
CClientDC dc(this);
CRect rc;
if ((nFlags & MK_LBUTTON)!=0)
{ int m_top,m_left,m_right,m_bottom;
if (m_LastPoint.x>m_TrackPoint.x)
{
m_left=m_TrackPoint.x;
m_right=m_LastPoint.x;
}
else
{
m_right=m_TrackPoint.x;
m_left=m_LastPoint.x;
}
if (m_LastPoint.y>m_TrackPoint.y)
{
m_top=m_TrackPoint.y;
m_bottom=m_LastPoint.y;
}
else
{
m_bottom=m_TrackPoint.y;
m_top=m_LastPoint.y;
}


rc.top=m_top;
rc.left=m_left;
rc.right=m_right;
rc.bottom=m_bottom;

DrawFocusRect(dc.m_hDC,rc);
if (m_LastPoint.x>point.x)
{
m_left=point.x;
m_right=m_LastPoint.x;
}
else
{
m_right=point.x;
m_left=m_LastPoint.x;
}
if (m_LastPoint.y>point.y)
{
m_top=point.y;
m_bottom=m_LastPoint.y;
}
else
{
m_bottom=point.y;
m_top=m_LastPoint.y;
}


rc.top=m_top;
rc.left=m_left;
rc.right=m_right;
rc.bottom=m_bottom;
DrawFocusRect(dc.m_hDC,rc);
m_TrackPoint=point;
}

CView::OnMouseMove(nFlags, point);
}