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Patch [ 942051 ] generic wxDCBase::DoGetPartialTextExtents speed improvement

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@26979 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Robin Dunn
2004-04-26 23:33:55 +00:00
parent 5ce4d9fa37
commit 174ee1b3d3
1 changed files with 56 additions and 7 deletions
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63
src/common/dcbase.cpp
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@@ -370,27 +370,76 @@ void wxDCBase::DoDrawSpline( wxList *points )
// ----------------------------------------------------------------------------
// Each element of the array will be the width of the string up to and
// Each element of the widths array will be the width of the string up to and
// including the coresoponding character in text. This is the generic
// implementation, the port-specific classes should do this with native APIs
// if available.
// if available and if faster. Note: pango_layout_index_to_pos is much slower
// than calling GetTextExtent!!
#define FWC_SIZE 128
class FontWidthCache
{
public:
FontWidthCache() : m_scaleX(1), m_widths(NULL) { }
~FontWidthCache() { delete []m_widths; }
void Reset()
{
if (!m_widths)
m_widths = new int[FWC_SIZE];
memset(m_widths, 0, sizeof(int)*FWC_SIZE);
}
wxFont m_font;
double m_scaleX;
int *m_widths;
};
static FontWidthCache s_fontWidthCache;
bool wxDCBase::DoGetPartialTextExtents(const wxString& text, wxArrayInt& widths) const
{
int totalWidth = 0;
size_t i;
size_t i, len = text.Length();
widths.Empty();
widths.Add(0, text.Length());
widths.Add(0, len);
int w, h;
// reset the cache if font or horizontal scale have changed
if (!s_fontWidthCache.m_widths ||
(s_fontWidthCache.m_scaleX != m_scaleX) ||
(s_fontWidthCache.m_font != GetFont()))
{
s_fontWidthCache.Reset();
s_fontWidthCache.m_font = GetFont();
s_fontWidthCache.m_scaleX = m_scaleX;
}
// Calculate the position of each character based on the widths of
// the previous characters
for (i=0; i<text.Length(); i++) {
int w, h;
GetTextExtent(text[i], &w, &h);
for (i=0; i<len; i++)
{
const wxChar c = text[i];
unsigned int c_int = (unsigned int)c;
if ((c_int < FWC_SIZE) && (s_fontWidthCache.m_widths[c_int] != 0))
{
w = s_fontWidthCache.m_widths[c_int];
}
else
{
GetTextExtent(c, &w, &h);
if (c_int < FWC_SIZE)
s_fontWidthCache.m_widths[c_int] = w;
}
totalWidth += w;
widths[i] = totalWidth;
}
return true;
}