Fix rounding error when setting brightness by percentage

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
(cherry picked from commit c3b2fad5e680e600fdee13981c43d342483d5635)

4 files changed, 31 insertions, 32 deletions

diff --git a/src/configuredialog.cpp b/src/configuredialog.cpp
index 1669d24..d453ce6 100644
--- a/src/configuredialog.cpp
+++ b/src/configuredialog.cpp
@@ -78,9 +78,9 @@ ConfigureDialog::ConfigureDialog( TDEConfig *_config, HardwareInfo *_hwinfo, Set
 	scheme_changed = false;
 	displayed_WARN_autosuspend = false;
 
-	// check if brightness is supporte
+	// check if brightness is supported
 	if(hwinfo->supportBrightness()) {
-		brightnessLevels = hwinfo->getMaxBrightnessLevel() -1;
+		brightnessLevels = hwinfo->getMaxBrightnessLevel();
 		brightness_last = hwinfo->getCurrentBrightnessLevel();
 	} else {
 		brightnessLevels = -1;
diff --git a/src/hardware.cpp b/src/hardware.cpp
index 25d96dd..ef1ba23 100644
--- a/src/hardware.cpp
+++ b/src/hardware.cpp
@@ -30,6 +30,7 @@
 
 // include global header
 #include <fcntl.h>
+#include <math.h>
 
 // include QT header
 #include <tqtimer.h>
@@ -956,7 +957,6 @@ bool HardwareInfo::setBrightnessPercentage(int percent)
 	if (trace) kdDebug() << funcinfo << "IN: " << " percent: " << percent << endl;
 
 	bool retval = false;
-	int maxBrightness = getMaxBrightnessLevel();
 
 	// Use the first backlight in the list
 	TDEGenericHardwareList hwlist = m_hwdevices->listByDeviceClass(TDEGenericDeviceType::Backlight);
@@ -969,22 +969,24 @@ bool HardwareInfo::setBrightnessPercentage(int percent)
 			checkBrightness();
 		}
 
-		// Make sure percentage is within valid range
-		if (percent < 0) {
-			percent = 0;
-		}
-		else if (percent > 100) {
-			percent = 100;
-		}
-		int level = (int)(maxBrightness * percent / 100.0);
-
 		if (!brightness) {
 			kdError() << "Change brightness not supported " << endl;
-		} else {
+		}
+		else {
+			// Make sure percentage is within valid range
+			if (percent < 0) {
+				percent = 0;
+			}
+			else if (percent > 100) {
+				percent = 100;
+			}
+
+			int level = (int)round(getMaxBrightnessLevel() * percent / 100.0);
 			if (currentBrightnessLevel == level) {
 				kdDebug() << "Brightness level not changed, requested level == current level" << endl;
 				retval = true;
-			} else {
+			}
+			else {
 				backlightdevice->setRawBrightness(level);
 				retval = true;
 			}
@@ -1181,10 +1183,9 @@ bool HardwareInfo::setBrightnessUp(int percentageStep) {
 
 	checkCurrentBrightness();
 
-	if (supportBrightness() && getCurrentBrightnessLevel() < getMaxBrightnessLevel() &&
-			percentageStep > 0)
+	if (supportBrightness() && percentageStep > 0)
 	{
-		int currentPerc = (int)(100.0 * getCurrentBrightnessLevel() / getMaxBrightnessLevel());
+		int currentPerc = (int)round(100.0 * getCurrentBrightnessLevel() / getMaxBrightnessLevel());
 		retval = setBrightnessPercentage(currentPerc + percentageStep);
 	}
 
@@ -1206,8 +1207,8 @@ bool HardwareInfo::setBrightnessDown(int percentageStep) {
 
 	checkCurrentBrightness();
 
-	if (supportBrightness() && getCurrentBrightnessLevel() > 0 && percentageStep > 0) {
-		int currentPerc = (int)(100.0 * getCurrentBrightnessLevel() / getMaxBrightnessLevel());
+	if (supportBrightness() && percentageStep > 0) {
+		int currentPerc = (int)round(100.0 * getCurrentBrightnessLevel() / getMaxBrightnessLevel());
 		retval = setBrightnessPercentage(currentPerc - percentageStep);
 	}
 
@@ -1245,7 +1246,7 @@ bool HardwareInfo::getLidclose() const {
  */
 int HardwareInfo::getMaxBrightnessLevel() const {
 	if (brightness)
-		return availableBrightnessLevels;
+		return availableBrightnessLevels - 1;
 	else
 		return -1;
 }
diff --git a/src/tdepowersave.cpp b/src/tdepowersave.cpp
index b57bfef..41ade35 100644
--- a/src/tdepowersave.cpp
+++ b/src/tdepowersave.cpp
@@ -23,6 +23,8 @@
 #include <config.h>
 #endif
 
+#include <math.h>
+
 // KDE headers:
 #include <tdeaboutapplication.h>
 #include <tdeapplication.h>
@@ -1073,7 +1075,7 @@ void tdepowersave::do_downDimm() {
 
 	if (hwinfo->supportBrightness()) {
 		if (!AUTODIMM_Timer->isActive()) {
-			int dimmToLevel = (int)((float)hwinfo->getMaxBrightnessLevel()*((float)settings->autoDimmTo/100.0));
+			int dimmToLevel = (int)round(hwinfo->getMaxBrightnessLevel() * settings->autoDimmTo / 100.0);
 
 			// check if we really need to dimm down
 			if (dimmToLevel < hwinfo->getCurrentBrightnessLevel()) {
@@ -1112,7 +1114,7 @@ void tdepowersave::do_upDimm() {
 
 	if (hwinfo->supportBrightness()) {
 		if (!AUTODIMM_Timer->isActive()) {
-			int dimmToLevel = (int)((float)hwinfo->getMaxBrightnessLevel()*((float)settings->brightnessValue/100.0));
+			int dimmToLevel = (int)round(hwinfo->getMaxBrightnessLevel() * settings->autoDimmTo / 100.0);
 
 			// check if we really need to dimm up
 			if (dimmToLevel > hwinfo->getCurrentBrightnessLevel()) {
@@ -1153,8 +1155,7 @@ void tdepowersave::do_dimm() {
 
 	if (autoDimmDown) {
 		// dimm the display down
-		if (current > 0 &&
-		    current > ((int)((float)hwinfo->getMaxBrightnessLevel()*((float)settings->autoDimmTo/100.0))-1)) {
+		if (current > (int)round(hwinfo->getMaxBrightnessLevel() * settings->autoDimmTo / 100.0)) {
 			hwinfo->setBrightnessLevel(current -1);
 		} else {
 			AUTODIMM_Timer->stop();
@@ -1166,7 +1167,7 @@ void tdepowersave::do_dimm() {
 		}
 	} else {
 		// dimm the display up
-		if (current < ((int)((float)hwinfo->getMaxBrightnessLevel()*((float)settings->brightnessValue/100.0))-1)) {
+		if (current < (int)round(hwinfo->getMaxBrightnessLevel() * settings->autoDimmTo / 100.0)) {
 			hwinfo->setBrightnessLevel(current +1);
 		} else {
 			AUTODIMM_Timer->stop();
@@ -2938,7 +2939,7 @@ int tdepowersave::brightnessGet() {
 	int retval = -1;
 
 	if (hwinfo->supportBrightness()) {
-		retval = (int)(100.0 * hwinfo->getCurrentBrightnessLevel() / hwinfo->getMaxBrightnessLevel());
+		retval = (int)round(100.0 * hwinfo->getCurrentBrightnessLevel() / hwinfo->getMaxBrightnessLevel());
 	}
 
 	kdDebugFuncOut(trace);
@@ -2951,10 +2952,7 @@ void tdepowersave::brightnessSet(int percentage)
 {
 	kdDebugFuncIn(trace);
 
-	if (hwinfo->supportBrightness() && percentage >= 0 && percentage <= 100)
-	{
-		hwinfo->setBrightnessPercentage(percentage);
-	}
+	hwinfo->setBrightnessPercentage(percentage);
 
 	kdDebugFuncOut(trace);
 }
diff --git a/src/tdepowersave.h b/src/tdepowersave.h
index 521184a..326d8be 100644
--- a/src/tdepowersave.h
+++ b/src/tdepowersave.h
@@ -440,8 +440,8 @@ k_dcop:
 	//! dcop function to open the configure dialog
 	bool openConfigureDialog();
 
-  //! dcop function to find out if tdepowersave manages DPMS
-  bool currentSchemeManagesDPMS();
+	//! dcop function to find out if tdepowersave manages DPMS
+	bool currentSchemeManagesDPMS();
 	//! dcop funtion to get the current brightness level
 	int brightnessGet();
 	//! dcop funtion to set the brightness level