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#include "config.h"
#include "ScrollbarThemeChromiumLinux.h"
#include "PlatformContextSkia.h"
#include "PlatformMouseEvent.h"
#include "RenderTheme.h"
#include "RenderThemeChromiumLinux.h"
#include "Scrollbar.h"
#include "TransformationMatrix.h"
namespace WebCore {
ScrollbarTheme* ScrollbarTheme::nativeTheme()
{
static ScrollbarThemeChromiumLinux theme;
return &theme;
}
int ScrollbarThemeChromiumLinux::scrollbarThickness(ScrollbarControlSize controlSize)
{
return 15;
}
static void drawVertLine(SkCanvas* canvas, int x, int y1, int y2, const SkPaint& paint)
{
SkIRect skrect;
skrect.set(x, y1, x + 1, y2 + 1);
canvas->drawIRect(skrect, paint);
}
static void drawHorizLine(SkCanvas* canvas, int x1, int x2, int y, const SkPaint& paint)
{
SkIRect skrect;
skrect.set(x1, y, x2 + 1, y + 1);
canvas->drawIRect(skrect, paint);
}
static void drawBox(SkCanvas* canvas, const IntRect& rect, const SkPaint& paint)
{
const int right = rect.x() + rect.width() - 1;
const int bottom = rect.y() + rect.height() - 1;
drawHorizLine(canvas, rect.x(), right, rect.y(), paint);
drawVertLine(canvas, right, rect.y(), bottom, paint);
drawHorizLine(canvas, rect.x(), right, bottom, paint);
drawVertLine(canvas, rect.x(), rect.y(), bottom, paint);
}
static SkScalar clamp(SkScalar value, SkScalar min, SkScalar max)
{
return std::min(std::max(value, min), max);
}
static SkColor saturateAndBrighten(SkScalar* hsv,
SkScalar saturateAmount,
SkScalar brightenAmount)
{
SkScalar color[3];
color[0] = hsv[0];
color[1] = clamp(hsv[1] + saturateAmount, 0.0, 1.0);
color[2] = clamp(hsv[2] + brightenAmount, 0.0, 1.0);
return SkHSVToColor(color);
}
static SkColor outlineColor(SkScalar* hsv1, SkScalar* hsv2)
{
// GTK Theme engines have way too much control over the layout of
// the scrollbar. We might be able to more closely approximate its
// look-and-feel, if we sent whole images instead of just colors
// from the browser to the renderer. But even then, some themes
// would just break.
//
// So, instead, we don't even try to 100% replicate the look of
// the native scrollbar. We render our own version, but we make
// sure to pick colors that blend in nicely with the system GTK
// theme. In most cases, we can just sample a couple of pixels
// from the system scrollbar and use those colors to draw our
// scrollbar.
//
// This works fine for the track color and the overall thumb
// color. But it fails spectacularly for the outline color used
// around the thumb piece. Not all themes have a clearly defined
// outline. For some of them it is partially transparent, and for
// others the thickness is very unpredictable.
//
// So, instead of trying to approximate the system theme, we
// instead try to compute a reasonable looking choice based on the
// known color of the track and the thumb piece. This is difficult
// when trying to deal both with high- and low-contrast themes,
// and both with positive and inverted themes.
//
// The following code has been tested to look OK with all of the
// default GTK themes.
SkScalar minDiff = clamp((hsv1[1] + hsv2[1]) * 1.2, 0.2, 0.5);
SkScalar diff = clamp(fabs(hsv1[2] - hsv2[2]) / 2, minDiff, 0.5);
if (hsv1[2] + hsv2[2] > 1.0)
diff = -diff;
return saturateAndBrighten(hsv2, -0.2, diff);
}
IntRect ScrollbarThemeChromium::trackRect(Scrollbar* scrollbar, bool)
{
IntSize bs = buttonSize(scrollbar);
int thickness = scrollbarThickness(scrollbar->controlSize());
if (scrollbar->orientation() == HorizontalScrollbar)
return IntRect(scrollbar->x() + bs.width(), scrollbar->y(), scrollbar->width(), thickness);
return IntRect(scrollbar->x(), scrollbar->y() + bs.height(), thickness, scrollbar->height());
}
void ScrollbarThemeChromiumLinux::paintTrackPiece(GraphicsContext* gc, Scrollbar* scrollbar, const IntRect& rect, ScrollbarPart partType)
{
SkCanvas* const canvas = gc->platformContext()->canvas();
SkPaint paint;
SkIRect skrect;
skrect.set(rect.x(), rect.y(), rect.x() + rect.width(), rect.y() + rect.height());
SkScalar track_hsv[3];
SkColorToHSV(RenderThemeChromiumLinux::trackColor(), track_hsv);
paint.setColor(saturateAndBrighten(track_hsv, 0, 0));
canvas->drawIRect(skrect, paint);
SkScalar thumb_hsv[3];
SkColorToHSV(RenderThemeChromiumLinux::thumbInactiveColor(),
thumb_hsv);
paint.setColor(outlineColor(track_hsv, thumb_hsv));
drawBox(canvas, rect, paint);
}
void ScrollbarThemeChromiumLinux::paintButton(GraphicsContext* gc, Scrollbar* scrollbar, const IntRect& rect, ScrollbarPart part)
{
// We don't use buttons
}
void ScrollbarThemeChromiumLinux::paintThumb(GraphicsContext* gc, Scrollbar* scrollbar, const IntRect& rect)
{
const bool hovered = scrollbar->hoveredPart() == ThumbPart;
const int midx = rect.x() + rect.width() / 2;
const int midy = rect.y() + rect.height() / 2;
const bool vertical = scrollbar->orientation() == VerticalScrollbar;
SkCanvas* const canvas = gc->platformContext()->canvas();
SkScalar thumb[3];
SkColorToHSV(hovered
? RenderThemeChromiumLinux::thumbActiveColor()
: RenderThemeChromiumLinux::thumbInactiveColor(),
thumb);
SkPaint paint;
paint.setColor(saturateAndBrighten(thumb, 0, 0.02));
SkIRect skrect;
if (vertical)
skrect.set(rect.x(), rect.y(), midx + 1, rect.y() + rect.height());
else
skrect.set(rect.x(), rect.y(), rect.x() + rect.width(), midy + 1);
canvas->drawIRect(skrect, paint);
paint.setColor(saturateAndBrighten(thumb, 0, -0.02));
if (vertical)
skrect.set(midx + 1, rect.y(), rect.x() + rect.width(), rect.y() + rect.height());
else
skrect.set(rect.x(), midy + 1, rect.x() + rect.width(), rect.y() + rect.height());
canvas->drawIRect(skrect, paint);
SkScalar track[3];
SkColorToHSV(RenderThemeChromiumLinux::trackColor(), track);
paint.setColor(outlineColor(track, thumb));
drawBox(canvas, rect, paint);
if (rect.height() > 10 && rect.width() > 10) {
const int grippyHalfWidth = 2;
const int interGrippyOffset = 3;
if (vertical) {
drawHorizLine(canvas, midx - grippyHalfWidth, midx + grippyHalfWidth, midy - interGrippyOffset, paint);
drawHorizLine(canvas, midx - grippyHalfWidth, midx + grippyHalfWidth, midy, paint);
drawHorizLine(canvas, midx - grippyHalfWidth, midx + grippyHalfWidth, midy + interGrippyOffset, paint);
} else {
drawVertLine(canvas, midx - interGrippyOffset, midy - grippyHalfWidth, midy + grippyHalfWidth, paint);
drawVertLine(canvas, midx, midy - grippyHalfWidth, midy + grippyHalfWidth, paint);
drawVertLine(canvas, midx + interGrippyOffset, midy - grippyHalfWidth, midy + grippyHalfWidth, paint);
}
}
}
bool ScrollbarThemeChromiumLinux::shouldCenterOnThumb(Scrollbar*, const PlatformMouseEvent& evt)
{
return (evt.shiftKey() && evt.button() == LeftButton) || (evt.button() == MiddleButton);
}
IntSize ScrollbarThemeChromiumLinux::buttonSize(Scrollbar* scrollbar)
{
// On Linux, we don't use buttons
return IntSize(0, 0);
}
int ScrollbarThemeChromiumLinux::minimumThumbLength(Scrollbar* scrollbar)
{
// This matches Firefox on Linux.
return 2 * scrollbarThickness(scrollbar->controlSize());
}
} // namespace WebCore