Source/WebCore/platform/chromium/PlatformThemeChromiumLinux.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"
 #include "PlatformThemeChromiumLinux.h"

 namespace WebCore {

 unsigned PlatformThemeChromiumLinux::s_thumbInactiveColor = 0xeaeaea;
 unsigned PlatformThemeChromiumLinux::s_thumbActiveColor = 0xf4f4f4;
 unsigned PlatformThemeChromiumLinux::s_trackColor = 0xd3d3d3;

 void PlatformThemeChromiumLinux::setScrollbarColors(
     SkColor inactiveColor, SkColor activeColor, SkColor trackColor)
 {
     s_thumbInactiveColor = inactiveColor;
     s_thumbActiveColor = activeColor;
     s_trackColor = trackColor;
 }

 static SkScalar clamp(SkScalar value, SkScalar min, SkScalar max)
 {
     return std::min(std::max(value, min), max);
 }

 SkColor PlatformThemeChromiumLinux::saturateAndBrighten(const SkScalar hsv[3], 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);
 }

 SkColor PlatformThemeChromiumLinux::outlineColor(const SkScalar hsv1[3], const SkScalar hsv2[3])
 {
     // 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, 0.28, 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);
 }

 void PlatformThemeChromiumLinux::paintArrowButton(GraphicsContext* gc, const IntRect& rect, ArrowDirection direction, ControlStates states)
 {
     SkCanvas* const canvas = gc->platformContext()->canvas();
     int widthMiddle, lengthMiddle;
     SkPaint paint;
     if (direction == North || direction == South) {
         widthMiddle = rect.width() / 2 + 1;
         lengthMiddle = rect.height() / 2 + 1;
     } else {
         lengthMiddle = rect.width() / 2 + 1;
         widthMiddle = rect.height() / 2 + 1;
     }

     // Calculate button color.
     SkScalar trackHSV[3];
     SkColorToHSV(trackColor(), trackHSV);
     SkColor buttonColor = saturateAndBrighten(trackHSV, 0, 0.2);
     SkColor backgroundColor = buttonColor;
     if (states & PressedState) {
         SkScalar buttonHSV[3];
         SkColorToHSV(buttonColor, buttonHSV);
         buttonColor = saturateAndBrighten(buttonHSV, 0, -0.1);
     } else if (states & HoverState) {
         SkScalar buttonHSV[3];
         SkColorToHSV(buttonColor, buttonHSV);
         buttonColor = saturateAndBrighten(buttonHSV, 0, 0.05);
     }

     SkIRect skrect;
     skrect.set(rect.x(), rect.y(), rect.x() + rect.width(), rect.y() + rect.height());
     // Paint the background (the area visible behind the rounded corners).
     paint.setColor(backgroundColor);
     canvas->drawIRect(skrect, paint);

     // Paint the button's outline and fill the middle
     SkPath outline;
     switch (direction) {
     case North:
         outline.moveTo(rect.x() + 0.5, rect.y() + rect.height() + 0.5);
         outline.rLineTo(0, -(rect.height() - 2));
         outline.rLineTo(2, -2);
         outline.rLineTo(rect.width() - 5, 0);
         outline.rLineTo(2, 2);
         outline.rLineTo(0, rect.height() - 2);
         break;
     case South:
         outline.moveTo(rect.x() + 0.5, rect.y() - 0.5);
         outline.rLineTo(0, rect.height() - 2);
         outline.rLineTo(2, 2);
         outline.rLineTo(rect.width() - 5, 0);
         outline.rLineTo(2, -2);
         outline.rLineTo(0, -(rect.height() - 2));
         break;
     case East:
         outline.moveTo(rect.x() - 0.5, rect.y() + 0.5);
         outline.rLineTo(rect.width() - 2, 0);
         outline.rLineTo(2, 2);
         outline.rLineTo(0, rect.height() - 5);
         outline.rLineTo(-2, 2);
         outline.rLineTo(-(rect.width() - 2), 0);
         break;
     case West:
         outline.moveTo(rect.x() + rect.width() + 0.5, rect.y() + 0.5);
         outline.rLineTo(-(rect.width() - 2), 0);
         outline.rLineTo(-2, 2);
         outline.rLineTo(0, rect.height() - 5);
         outline.rLineTo(2, 2);
         outline.rLineTo(rect.width() - 2, 0);
         break;
     }
     outline.close();

     paint.setStyle(SkPaint::kFill_Style);
     paint.setColor(buttonColor);
     canvas->drawPath(outline, paint);

     paint.setAntiAlias(true);
     paint.setStyle(SkPaint::kStroke_Style);
     SkScalar thumbHSV[3];
     SkColorToHSV(thumbInactiveColor(), thumbHSV);
     paint.setColor(outlineColor(trackHSV, thumbHSV));
     canvas->drawPath(outline, paint);

     // If the button is disabled or read-only, the arrow is drawn with the outline color.
     if (states & EnabledState && !(states & ReadOnlyState))
         paint.setColor(SK_ColorBLACK);

     paint.setAntiAlias(false);
     paint.setStyle(SkPaint::kFill_Style);

     SkPath path;
     // The constants in this block of code are hand-tailored to produce good
     // looking arrows without anti-aliasing.
     switch (direction) {
     case North:
         path.moveTo(rect.x() + widthMiddle - 4, rect.y() + lengthMiddle + 2);
         path.rLineTo(7, 0);
         path.rLineTo(-4, -4);
         break;
     case South:
         path.moveTo(rect.x() + widthMiddle - 4, rect.y() + lengthMiddle - 3);
         path.rLineTo(7, 0);
         path.rLineTo(-4, 4);
         break;
     case East:
         path.moveTo(rect.x() + lengthMiddle - 3, rect.y() + widthMiddle - 4);
         path.rLineTo(0, 7);
         path.rLineTo(4, -4);
         break;
     case West:
         path.moveTo(rect.x() + lengthMiddle + 1, rect.y() + widthMiddle - 5);
         path.rLineTo(0, 9);
         path.rLineTo(-4, -4);
         break;
     }
     path.close();

     canvas->drawPath(path, paint);
 }

 } // namespace WebCore
	/*
	* Copyright (C) 2011 Google Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"
	#include "PlatformThemeChromiumLinux.h"

	namespace WebCore {

	unsigned PlatformThemeChromiumLinux::s_thumbInactiveColor = 0xeaeaea;
	unsigned PlatformThemeChromiumLinux::s_thumbActiveColor = 0xf4f4f4;
	unsigned PlatformThemeChromiumLinux::s_trackColor = 0xd3d3d3;

	void PlatformThemeChromiumLinux::setScrollbarColors(
	SkColor inactiveColor, SkColor activeColor, SkColor trackColor)
	{
	s_thumbInactiveColor = inactiveColor;
	s_thumbActiveColor = activeColor;
	s_trackColor = trackColor;
	}

	static SkScalar clamp(SkScalar value, SkScalar min, SkScalar max)
	{
	return std::min(std::max(value, min), max);
	}

	SkColor PlatformThemeChromiumLinux::saturateAndBrighten(const SkScalar hsv[3], 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);
	}

	SkColor PlatformThemeChromiumLinux::outlineColor(const SkScalar hsv1[3], const SkScalar hsv2[3])
	{
	// 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, 0.28, 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);
	}

	void PlatformThemeChromiumLinux::paintArrowButton(GraphicsContext* gc, const IntRect& rect, ArrowDirection direction, ControlStates states)
	{
	SkCanvas* const canvas = gc->platformContext()->canvas();
	int widthMiddle, lengthMiddle;
	SkPaint paint;
	if (direction == North \|\| direction == South) {
	widthMiddle = rect.width() / 2 + 1;
	lengthMiddle = rect.height() / 2 + 1;
	} else {
	lengthMiddle = rect.width() / 2 + 1;
	widthMiddle = rect.height() / 2 + 1;
	}

	// Calculate button color.
	SkScalar trackHSV[3];
	SkColorToHSV(trackColor(), trackHSV);
	SkColor buttonColor = saturateAndBrighten(trackHSV, 0, 0.2);
	SkColor backgroundColor = buttonColor;
	if (states & PressedState) {
	SkScalar buttonHSV[3];
	SkColorToHSV(buttonColor, buttonHSV);
	buttonColor = saturateAndBrighten(buttonHSV, 0, -0.1);
	} else if (states & HoverState) {
	SkScalar buttonHSV[3];
	SkColorToHSV(buttonColor, buttonHSV);
	buttonColor = saturateAndBrighten(buttonHSV, 0, 0.05);
	}

	SkIRect skrect;
	skrect.set(rect.x(), rect.y(), rect.x() + rect.width(), rect.y() + rect.height());
	// Paint the background (the area visible behind the rounded corners).
	paint.setColor(backgroundColor);
	canvas->drawIRect(skrect, paint);

	// Paint the button's outline and fill the middle
	SkPath outline;
	switch (direction) {
	case North:
	outline.moveTo(rect.x() + 0.5, rect.y() + rect.height() + 0.5);
	outline.rLineTo(0, -(rect.height() - 2));
	outline.rLineTo(2, -2);
	outline.rLineTo(rect.width() - 5, 0);
	outline.rLineTo(2, 2);
	outline.rLineTo(0, rect.height() - 2);
	break;
	case South:
	outline.moveTo(rect.x() + 0.5, rect.y() - 0.5);
	outline.rLineTo(0, rect.height() - 2);
	outline.rLineTo(2, 2);
	outline.rLineTo(rect.width() - 5, 0);
	outline.rLineTo(2, -2);
	outline.rLineTo(0, -(rect.height() - 2));
	break;
	case East:
	outline.moveTo(rect.x() - 0.5, rect.y() + 0.5);
	outline.rLineTo(rect.width() - 2, 0);
	outline.rLineTo(2, 2);
	outline.rLineTo(0, rect.height() - 5);
	outline.rLineTo(-2, 2);
	outline.rLineTo(-(rect.width() - 2), 0);
	break;
	case West:
	outline.moveTo(rect.x() + rect.width() + 0.5, rect.y() + 0.5);
	outline.rLineTo(-(rect.width() - 2), 0);
	outline.rLineTo(-2, 2);
	outline.rLineTo(0, rect.height() - 5);
	outline.rLineTo(2, 2);
	outline.rLineTo(rect.width() - 2, 0);
	break;
	}
	outline.close();

	paint.setStyle(SkPaint::kFill_Style);
	paint.setColor(buttonColor);
	canvas->drawPath(outline, paint);

	paint.setAntiAlias(true);
	paint.setStyle(SkPaint::kStroke_Style);
	SkScalar thumbHSV[3];
	SkColorToHSV(thumbInactiveColor(), thumbHSV);
	paint.setColor(outlineColor(trackHSV, thumbHSV));
	canvas->drawPath(outline, paint);

	// If the button is disabled or read-only, the arrow is drawn with the outline color.
	if (states & EnabledState && !(states & ReadOnlyState))
	paint.setColor(SK_ColorBLACK);

	paint.setAntiAlias(false);
	paint.setStyle(SkPaint::kFill_Style);

	SkPath path;
	// The constants in this block of code are hand-tailored to produce good
	// looking arrows without anti-aliasing.
	switch (direction) {
	case North:
	path.moveTo(rect.x() + widthMiddle - 4, rect.y() + lengthMiddle + 2);
	path.rLineTo(7, 0);
	path.rLineTo(-4, -4);
	break;
	case South:
	path.moveTo(rect.x() + widthMiddle - 4, rect.y() + lengthMiddle - 3);
	path.rLineTo(7, 0);
	path.rLineTo(-4, 4);
	break;
	case East:
	path.moveTo(rect.x() + lengthMiddle - 3, rect.y() + widthMiddle - 4);
	path.rLineTo(0, 7);
	path.rLineTo(4, -4);
	break;
	case West:
	path.moveTo(rect.x() + lengthMiddle + 1, rect.y() + widthMiddle - 5);
	path.rLineTo(0, 9);
	path.rLineTo(-4, -4);
	break;
	}
	path.close();

	canvas->drawPath(path, paint);
	}

	} // namespace WebCore