duilib中的V和H布局中滚动条问题
首先看一段xml代码
这是一个窗口，它包含一个竖的布局，显示出来初始状态是这样的：
在布局中，2个子控件所需要的长和宽，比布局本身的大小要大，所以需要2个滚动条来拉动显示。
我们可以看到横竖两个滚动条。
不过，我们拉动滚动条，却不能完全展示子控件。如下图：
虽然横向滚动条拉到了最右边，但Label控件child1的右边没有展示出来。
检查代码，发现CVerticalLayoutUI的SetPos方法如下：
void CVerticalLayoutUI::SetPos(RECT rc)
{
...省略若干代码
// Process the scrollbar
ProcessScrollBar(rc, 0, cyNeeded);
}在最后面，调用了基类CContainerUI的ProcessScrollBar方法，来设置滚动条信息，ProcessScrollBar函数的第二个参数是设置横向滚动条信息，第三个参数是竖向滚动条。此时设置横向的参数为0，竖向的是cyNeeded。显然，这里忽略了横向的，所以在竖向布局VerticalLayout中，横向滚动条不能正常显示。
在CVerticalLayoutUI::SetPos中，所有涉及到cyNeeded的代码如下：
int cyNeeded = 0;
int cyExpand = 0;
if( nAdjustables > 0 ) cyExpand = MAX(0, (szAvailable.cy - cyFixed) / nAdjustables);
// Position the elements
SIZE szRemaining = szAvailable;
int iPosY = rc.top;
if( m_pVerticalScrollBar && m_pVerticalScrollBar->IsVisible() ) {
iPosY -= m_pVerticalScrollBar->GetScrollPos();
}
int iPosX = rc.left;
if( m_pHorizontalScrollBar && m_pHorizontalScrollBar->IsVisible() ) {
iPosX -= m_pHorizontalScrollBar->GetScrollPos();
}
int iAdjustable = 0;
int cyFixedRemaining = cyFixed;
for( int it2 = 0; it2 < m_items.GetSize(); it2++ ) {
CControlUI* pControl = static_cast(m_items[it2]);
if( !pControl->IsVisible() ) continue;
if( pControl->IsFloat() ) {
SetFloatPos(it2);
continue;
}
RECT rcPadding = pControl->GetPadding();
szRemaining.cy -= rcPadding.top;
SIZE sz = pControl->EstimateSize(szRemaining);
if( sz.cy == 0 ) {
iAdjustable++;
sz.cy = cyExpand;
// Distribute remaining to last element (usually round-off left-overs)
if( iAdjustable == nAdjustables ) {
sz.cy = MAX(0, szRemaining.cy - rcPadding.bottom - cyFixedRemaining);
}
if( sz.cy < pControl->GetMinHeight() ) sz.cy = pControl->GetMinHeight();
if( sz.cy > pControl->GetMaxHeight() ) sz.cy = pControl->GetMaxHeight();
}
else {
if( sz.cy < pControl->GetMinHeight() ) sz.cy = pControl->GetMinHeight();
if( sz.cy > pControl->GetMaxHeight() ) sz.cy = pControl->GetMaxHeight();
cyFixedRemaining -= sz.cy;
}
sz.cx = pControl->GetFixedWidth();
if( sz.cx == 0 ) sz.cx = szAvailable.cx - rcPadding.left - rcPadding.right;
if( sz.cx < 0 ) sz.cx = 0;
if( sz.cx < pControl->GetMinWidth() ) sz.cx = pControl->GetMinWidth();
if( sz.cx > pControl->GetMaxWidth() ) sz.cx = pControl->GetMaxWidth();
RECT rcCtrl = { iPosX + rcPadding.left, iPosY + rcPadding.top, iPosX + rcPadding.left + sz.cx, iPosY + sz.cy + rcPadding.top + rcPadding.bottom };
pControl->SetPos(rcCtrl);
iPosY += sz.cy + m_iChildPadding + rcPadding.top + rcPadding.bottom;
cyNeeded += sz.cy + rcPadding.top + rcPadding.bottom;
szRemaining.cy -= sz.cy + m_iChildPadding + rcPadding.bottom;
}
cyNeeded += (nEstimateNum - 1) * m_iChildPadding; 在 cyNeeded += sz.cy + rcPadding.top + rcPadding.bottom; 里，sz.cy是1个子控件的高度，而rcPadding = pControl->GetPadding(); 是控件的padding属性，也就是外边距。
最后yNeeded += (nEstimateNum - 1) * m_iChildPadding; m_iChildPadding是布局的childpadding属性，也就是子控件之间的额外距离。
我们可以仿照cyNeeded的计算方式，来算出cxNeeded。因为是竖向布局，所以 cyNeeded += sz.cy 这里是累加，但是横向值，应该取最宽的控件的值，
所以for循环中的代码应该是这样：
int tmp = sz.cx + rcPadding.left + rcPadding.right;
cxNeeded = (tmp > cxNeeded) ? tmp: cxNeeded;
最后cxNeeded += (nEstimateNum - 1) * m_iChildPadding;
此时通过对代码的了解，可以得知：布局在计算容量面积时，只计算非float类型的子控件，忽略了float类型的子控件。
算出了布局的宽度后，就应用起来
修改原来的代码为：ProcessScrollBar(rc, cxNeeded, cyNeeded);
改完后，发现问题依然。于是，检查了下ProcessScrollBar的代码，如下
void CContainerUI::ProcessScrollBar(RECT rc, int cxRequired, int cyRequired)
{
if( m_pHorizontalScrollBar != NULL && m_pHorizontalScrollBar->IsVisible() ) {
RECT rcScrollBarPos = { rc.left, rc.bottom, rc.right, rc.bottom + m_pHorizontalScrollBar->GetFixedHeight()};
m_pHorizontalScrollBar->SetPos(rcScrollBarPos);
}
if( m_pVerticalScrollBar == NULL ) return;
if( cyRequired > rc.bottom - rc.top && !m_pVerticalScrollBar->IsVisible() ) {
m_pVerticalScrollBar->SetVisible(true);
m_pVerticalScrollBar->SetScrollRange(cyRequired - (rc.bottom - rc.top));
m_pVerticalScrollBar->SetScrollPos(0);
m_bScrollProcess = true;
SetPos(m_rcItem);
m_bScrollProcess = false;
return;
}
// No scrollbar required
if( !m_pVerticalScrollBar->IsVisible() ) return;
// Scroll not needed anymore?
int cyScroll = cyRequired - (rc.bottom - rc.top);
if( cyScroll <= 0 && !m_bScrollProcess) {
m_pVerticalScrollBar->SetVisible(false);
m_pVerticalScrollBar->SetScrollPos(0);
m_pVerticalScrollBar->SetScrollRange(0);
SetPos(m_rcItem);
}
else
{
RECT rcScrollBarPos = { rc.right, rc.top, rc.right + m_pVerticalScrollBar->GetFixedWidth(), rc.bottom };
m_pVerticalScrollBar->SetPos(rcScrollBarPos);
if( m_pVerticalScrollBar->GetScrollRange() != cyScroll ) {
int iScrollPos = m_pVerticalScrollBar->GetScrollPos();
m_pVerticalScrollBar->SetScrollRange(::abs(cyScroll));
if( m_pVerticalScrollBar->GetScrollRange() == 0 ) {
m_pVerticalScrollBar->SetVisible(false);
m_pVerticalScrollBar->SetScrollPos(0);
}
if( iScrollPos > m_pVerticalScrollBar->GetScrollPos() ) {
SetPos(m_rcItem);
}
}
}
}对于横向滚动条，只使用了这3行代码：
if( m_pHorizontalScrollBar != NULL && m_pHorizontalScrollBar->IsVisible() ) {
RECT rcScrollBarPos = { rc.left, rc.bottom, rc.right, rc.bottom + m_pHorizontalScrollBar->GetFixedHeight()};
m_pHorizontalScrollBar->SetPos(rcScrollBarPos);
}void CContainerUI::ProcessScrollBar(RECT rc, int cxRequired, int cyRequired)
{
while(m_pHorizontalScrollBar)
{
if (cxRequired > rc.right - rc.left && !m_pHorizontalScrollBar->IsVisible())
{
m_pHorizontalScrollBar->SetVisible(true);
m_pHorizontalScrollBar->SetScrollRange(cxRequired - (rc.right - rc.left));
m_pHorizontalScrollBar->SetScrollPos(0);
m_bScrollProcess = true;
SetPos(m_rcItem);
m_bScrollProcess = false;
break;
}
if( !m_pHorizontalScrollBar->IsVisible() ) break;
int cxScroll = cxRequired - (rc.right - rc.left);
if (cxScroll <= 0 && !m_bScrollProcess)
{
m_pHorizontalScrollBar->SetVisible(false);
m_pHorizontalScrollBar->SetScrollPos(0);
m_pHorizontalScrollBar->SetScrollRange(0);
SetPos(m_rcItem);
}
else
{
RECT rcScrollBarPos = { rc.left, rc.bottom, rc.right, rc.bottom + m_pHorizontalScrollBar->GetFixedHeight() };
m_pHorizontalScrollBar->SetPos(rcScrollBarPos);
if( m_pHorizontalScrollBar->GetScrollRange() != cxScroll ) {
int iScrollPos = m_pHorizontalScrollBar->GetScrollPos();
m_pHorizontalScrollBar->SetScrollRange(::abs(cxScroll));
if( m_pHorizontalScrollBar->GetScrollRange() == 0 ) {
m_pHorizontalScrollBar->SetVisible(false);
m_pHorizontalScrollBar->SetScrollPos(0);
}
if( iScrollPos > m_pHorizontalScrollBar->GetScrollPos() ) {
SetPos(m_rcItem);
}
}
}
break;
}
while(m_pVerticalScrollBar)
{
if( cyRequired > rc.bottom - rc.top && !m_pVerticalScrollBar->IsVisible() ) {
m_pVerticalScrollBar->SetVisible(true);
m_pVerticalScrollBar->SetScrollRange(cyRequired - (rc.bottom - rc.top));
m_pVerticalScrollBar->SetScrollPos(0);
m_bScrollProcess = true;
SetPos(m_rcItem);
m_bScrollProcess = false;
break;
}
// No scrollbar required
if( !m_pVerticalScrollBar->IsVisible() ) break;
// Scroll not needed anymore?
int cyScroll = cyRequired - (rc.bottom - rc.top);
if( cyScroll <= 0 && !m_bScrollProcess) {
m_pVerticalScrollBar->SetVisible(false);
m_pVerticalScrollBar->SetScrollPos(0);
m_pVerticalScrollBar->SetScrollRange(0);
SetPos(m_rcItem);
}
else
{
RECT rcScrollBarPos = { rc.right, rc.top, rc.right + m_pVerticalScrollBar->GetFixedWidth(), rc.bottom };
m_pVerticalScrollBar->SetPos(rcScrollBarPos);
if( m_pVerticalScrollBar->GetScrollRange() != cyScroll ) {
int iScrollPos = m_pVerticalScrollBar->GetScrollPos();
m_pVerticalScrollBar->SetScrollRange(::abs(cyScroll));
if( m_pVerticalScrollBar->GetScrollRange() == 0 ) {
m_pVerticalScrollBar->SetVisible(false);
m_pVerticalScrollBar->SetScrollPos(0);
}
if( iScrollPos > m_pVerticalScrollBar->GetScrollPos() ) {
SetPos(m_rcItem);
}
}
}
break;
}
}看看效果
可以看到控件child1的右边框。
HorizontalLayout也有同样的问题，可类似修改。