关于视图中滚动条的一个小问题。

[PM0115]

我建立了一个单文档工程，在客户区中显示我打开的bmp图片，由于bmp图片的象素是不同的，所以有些图片必须用滚动条拖动来查看，现在我的问题就是如何设置函数：SetScrollSizes()中的参数，使得水平和垂直滚动条的范围恰好等于图片的宽和长，我现在只能象下面一样这样硬性设置：SetScrollSizes(MM_TEXT,1000)。
如果大家方便的话不妨把SetScrollSizes()中的各个参数的意义给我说一下，谢谢大家了！！

[jerry]

void SetScrollSizes( int nMapMode, SIZE sizeTotal, const SIZE& sizePage = sizeDefault, const SIZE& sizeLine = sizeDefault );

Parameters

nMapMode

The mapping mode to set for this view. Possible values include:

Mapping Mode Logical Unit Positive y-axis Extends...
MM_TEXT 1 pixel Downward
MM_HIMETRIC 0.01 mm Upward
MM_TWIPS 1/1440 in Upward
MM_HIENGLISH 0.001 in Upward
MM_LOMETRIC 0.1 mm Upward
MM_LOENGLISH 0.01 in Upward


All of these modes are defined by Windows. Two standard mapping modes, MM_ISOTROPIC and MM_ANISOTROPIC, are not used for CScrollView. The class library provides the SetScaleToFitSize member function for scaling the view to window size. Column three in the table above describes the coordinate orientation.

sizeTotal

The total size of the scroll view. The cx member contains the horizontal extent. The cy member contains the vertical extent. Sizes are in logical units. Both cx and cy must be greater than or equal to 0.

sizePage

The horizontal and vertical amounts to scroll in each direction in response to a mouse click in a scroll-bar shaft. The cx member contains the horizontal amount. The cy member contains the vertical amount.

sizeLine

The horizontal and vertical amounts to scroll in each direction in response to a mouse click in a scroll arrow. The cx member contains the horizontal amount. The cy member contains the vertical amount.



for example, the size of bitmap is 800(w) X 600(h), you can use this function as following:

SetScrollSizes(MM_TEXT, CSize(800, 600));

[思危]

CBitmap bmp;
bmp.LoadBitmap(IDB_BMP1);
BITMAP info;
bmp.GetBitmap(&info);
SetScrollSizes(MM_TEXT, CSize(info.bmWidth, info.bmHeight));

[believefym]

恭喜楼上的升三星啊：）

[PM0115]

TO 思危：我像你这样设置：SetScrollSizes(MM_TEXT, CSize(info.bmWidth, info.bmHeight));后，一运行程序就出错，不知道怎么回事，谢谢！

[jerry]

info.bmWidth, info.bmHeight 确定要大于0 , 否则会出错.

可以这样: 如果info.bmWidth, info.bmHeight 是<=0 则给一个默认值如(1)

[jerry]

bmp.GetBitmap(&info); 也必需在图像有效时才能用.

[PM0115]

我本来是想这样添代码的：比如当我往右拉动滚动条时，这个时候就重新显示图片，而且根据我拉动的多少按比例显示图象的指定部分，这样看起来也达到了拖动图象以达到能完整地观看到全图的目的。但是细细想来这样不可取，每次拉动都另外显示的话，当图象很大时就会很慢，而且我不知道该如何判断是往左拖动还是往右拖动。
所以不知道MFC是否在上面两个消息处理函数中封装了相应的代码？还请大家帮帮我呀！谢谢了！

[PM0115]

我现在是像下面这样设置的，滚动条出现了，但是当我拖动滚动条时，图象并没有滚动，也就是说我该如何触发滚动事件，请大家帮我补充一下，谢谢！！

//程序开始时初始化滚动条
void CDIPView::OnInitialUpdate()
{

CScrollView::OnInitialUpdate();
CSize sizeTotal;

// TODO: calculate the total size of this view
sizeTotal.cx = 100;
sizeTotal.cy = 100;
SetScrollSizes( MM_TEXT, sizeTotal);

}

//当我调入一个图象进入内存并显示出来后就将垂直和水平滚动条设置为图象的高和宽
void CDIPView::OnOpenDib()
{
.........
.........
CSize sizeTotal;
CSize sizePage;
CSize sizeLine;

sizeTotal.cx = CMyDIB::pBitmapInfoHeader->biWidth;
sizeTotal.cy = CMyDIB::pBitmapInfoHeader->biHeight;

CScrollView::SetScrollSizes( MM_TEXT, sizeTotal , sizePage , sizeLine);
........
........
}

//然后我添加了垂直和水平滚动条的消息处理函数如下:
void CDIPView::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO: Add your message handler code here and/or call default

CScrollView::OnHScroll(nSBCode, nPos, pScrollBar);

}

void CDIPView::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO: Add your message handler code here and/or call default

CScrollView::OnVScroll(nSBCode, nPos, pScrollBar);
}

现在问题就是我该如何在上面两个消息处理函数中添加代码,使得我拖动滚动条时图象也随之跟着被拖动.
谢谢各位了!!

[PM0115]

哎，还是自己再顶一下，分不够再加呀！