int ScrollbarTheme::thumbLength(ScrollbarThemeClient* scrollbar)
{
if (!scrollbar->enabled())
return 0;
// It is safe to compute the overhang by adding the result from the main
// thread overscroll mode (first) and then adding the result from compositor
// thread overscroll (second) because the modes are mutually exclusive (and
// determining which mode is in use here will require lots of temporary
// plumbing, and the main thread mode is to be deleted).
float overhang = 0;
if (scrollbar->currentPos() < 0)
overhang = -scrollbar->currentPos();
else if (scrollbar->visibleSize() + scrollbar->currentPos() > scrollbar->totalSize())
overhang = scrollbar->currentPos() + scrollbar->visibleSize() - scrollbar->totalSize();
overhang += fabsf(scrollbar->elasticOverscroll());
float proportion = 0.0f;
float totalSize = usedTotalSize(scrollbar);
if (totalSize > 0.0f) {
proportion = (scrollbar->visibleSize() - overhang) / totalSize;
}
int trackLen = trackLength(scrollbar);
int length = round(proportion * trackLen);
length = std::max(length, minimumThumbLength(scrollbar));
if (length > trackLen)
length = 0; // Once the thumb is below the track length, it just goes away (to make more room for the track).
return length;
}
int Scrollbar::thumbLength()
{
int trackLen = trackLength();
if (!totalSize())
return trackLen;
float proportion = static_cast<float>(visibleSize()) / totalSize();
int length = round(proportion * trackLen);
length = std::min(std::max(length, minimumThumbLength()), trackLen);
return length;
}
int ScrollbarThemeOverlay::thumbLength(ScrollbarThemeClient* scrollbar)
{
int trackLen = trackLength(scrollbar);
if (!scrollbar->totalSize())
return trackLen;
float proportion = static_cast<float>(scrollbar->visibleSize()) / scrollbar->totalSize();
int length = round(proportion * trackLen);
length = std::min(std::max(length, minimumThumbLength(scrollbar)), trackLen);
return length;
}
int ScrollbarThemeComposite::thumbLength(Scrollbar* scrollbar)
{
if (!scrollbar->enabled())
return 0;
float proportion = (float)scrollbar->visibleSize() / scrollbar->totalSize();
int trackLen = trackLength(scrollbar);
int length = proportion * trackLen;
length = max(length, minimumThumbLength(scrollbar));
if (length > trackLen)
length = 0; // Once the thumb is below the track length, it just goes away (to make more room for the track).
return length;
}
int ScrollbarThemeOverlay::thumbLength(const ScrollbarThemeClient& scrollbar)
{
int trackLen = trackLength(scrollbar);
if (!scrollbar.totalSize())
return trackLen;
float proportion = static_cast<float>(scrollbar.visibleSize()) / scrollbar.totalSize();
int length = round(proportion * trackLen);
int minLen = std::min(minimumThumbLength(scrollbar), trackLen);
length = clampTo(length, minLen, trackLen);
return length;
}
int ScrollbarThemeComposite::thumbLength(ScrollbarThemeClient* scrollbar)
{
if (!scrollbar->enabled())
return 0;
float proportion = scrollbar->visibleSize() / usedTotalSize(scrollbar);
int trackLen = trackLength(scrollbar);
#if PLATFORM(MAC) && !PLATFORM(CHROMIUM)
int length = round(proportion * trackLen);
#else
int length = proportion * trackLen;
#endif
length = max(length, minimumThumbLength(scrollbar));
if (length > trackLen)
length = 0; // Once the thumb is below the track length, it just goes away (to make more room for the track).
return length;
}
int ScrollbarTheme::thumbLength(const ScrollbarThemeClient* scrollbar)
{
if (!scrollbar->enabled())
return 0;
float overhang = fabsf(scrollbar->elasticOverscroll());
float proportion = 0.0f;
float totalSize = scrollbar->totalSize();
if (totalSize > 0.0f) {
proportion = (scrollbar->visibleSize() - overhang) / totalSize;
}
int trackLen = trackLength(scrollbar);
int length = round(proportion * trackLen);
length = std::max(length, minimumThumbLength(scrollbar));
if (length > trackLen)
length = 0; // Once the thumb is below the track length, it just goes away (to make more room for the track).
return length;
}
int ScrollbarTheme::thumbLength(ScrollbarThemeClient* scrollbar)
{
if (!scrollbar->enabled())
return 0;
float overhang = 0;
if (scrollbar->currentPos() < 0)
overhang = -scrollbar->currentPos();
else if (scrollbar->visibleSize() + scrollbar->currentPos() > scrollbar->totalSize())
overhang = scrollbar->currentPos() + scrollbar->visibleSize() - scrollbar->totalSize();
float proportion = (scrollbar->visibleSize() - overhang) / usedTotalSize(scrollbar);
int trackLen = trackLength(scrollbar);
int length = round(proportion * trackLen);
length = std::max(length, minimumThumbLength(scrollbar));
if (length > trackLen)
length = 0; // Once the thumb is below the track length, it just goes away (to make more room for the track).
return length;
}