diff options
| -rw-r--r-- | services/inputflinger/reader/mapper/TouchpadInputMapper.cpp | 81 |
1 files changed, 77 insertions, 4 deletions
diff --git a/services/inputflinger/reader/mapper/TouchpadInputMapper.cpp b/services/inputflinger/reader/mapper/TouchpadInputMapper.cpp index 9f32311e14..8ab6748bfe 100644 --- a/services/inputflinger/reader/mapper/TouchpadInputMapper.cpp +++ b/services/inputflinger/reader/mapper/TouchpadInputMapper.cpp @@ -16,6 +16,7 @@ #include "../Macros.h" +#include <limits> #include <optional> #include <android/input.h> @@ -30,6 +31,76 @@ namespace android { namespace { +// Describes a segment of the acceleration curve. +struct CurveSegment { + // The maximum pointer speed which this segment should apply. The last segment in a curve should + // always set this to infinity. + double maxPointerSpeedMmPerS; + double slope; + double intercept; +}; + +const std::vector<CurveSegment> segments = { + {10.922, 3.19, 0}, + {31.750, 4.79, -17.526}, + {98.044, 7.28, -96.52}, + {std::numeric_limits<double>::infinity(), 15.04, -857.758}, +}; + +const std::vector<double> sensitivityFactors = {1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 18, 20}; + +std::vector<double> createAccelerationCurveForSensitivity(int32_t sensitivity, + size_t propertySize) { + LOG_ALWAYS_FATAL_IF(propertySize < 4 * segments.size()); + std::vector<double> output(propertySize, 0); + + // The Gestures library uses functions of the following form to define curve segments, where a, + // b, and c can be specified by us: + // output_speed(input_speed_mm) = a * input_speed_mm ^ 2 + b * input_speed_mm + c + // + // (a, b, and c are also called sqr_, mul_, and int_ in the Gestures library code.) + // + // We are trying to implement the following function, where slope and intercept are the + // parameters specified in the `segments` array above: + // gain(input_speed_mm) = + // 0.64 * (sensitivityFactor / 10) * (slope + intercept / input_speed_mm) + // Where "gain" is a multiplier applied to the input speed to produce the output speed: + // output_speed(input_speed_mm) = input_speed_mm * gain(input_speed_mm) + // + // To put our function in the library's form, we substitute it into the function above: + // output_speed(input_speed_mm) = + // input_speed_mm * (0.64 * (sensitivityFactor / 10) * + // (slope + 25.4 * intercept / input_speed_mm)) + // then expand the brackets so that input_speed_mm cancels out for the intercept term: + // gain(input_speed_mm) = + // 0.64 * (sensitivityFactor / 10) * slope * input_speed_mm + + // 0.64 * (sensitivityFactor / 10) * intercept + // + // This gives us the following parameters for the Gestures library function form: + // a = 0 + // b = 0.64 * (sensitivityFactor / 10) * slope + // c = 0.64 * (sensitivityFactor / 10) * intercept + + double commonFactor = 0.64 * sensitivityFactors[sensitivity + 7] / 10; + + size_t i = 0; + for (CurveSegment seg : segments) { + // The library's curve format consists of four doubles per segment: + // * maximum pointer speed for the segment (mm/s) + // * multiplier for the x² term (a.k.a. "a" or "sqr") + // * multiplier for the x term (a.k.a. "b" or "mul") + // * the intercept (a.k.a. "c" or "int") + // (see struct CurveSegment in the library's AccelFilterInterpreter) + output[i + 0] = seg.maxPointerSpeedMmPerS; + output[i + 1] = 0; + output[i + 2] = commonFactor * seg.slope; + output[i + 3] = commonFactor * seg.intercept; + i += 4; + } + + return output; +} + short getMaxTouchCount(const InputDeviceContext& context) { if (context.hasScanCode(BTN_TOOL_QUINTTAP)) return 5; if (context.hasScanCode(BTN_TOOL_QUADTAP)) return 4; @@ -147,10 +218,12 @@ std::list<NotifyArgs> TouchpadInputMapper::configure(nsecs_t when, mGestureConverter.setOrientation(orientation); } if (!changes || (changes & InputReaderConfiguration::CHANGE_TOUCHPAD_SETTINGS)) { - // TODO(b/265798483): load an Android-specific acceleration curve instead of mapping to one - // of five ChromeOS curves. - const int pointerSensitivity = (config->touchpadPointerSpeed + 7) / 3 + 1; - mPropertyProvider.getProperty("Pointer Sensitivity").setIntValues({pointerSensitivity}); + mPropertyProvider.getProperty("Use Custom Touchpad Pointer Accel Curve") + .setBoolValues({true}); + GesturesProp accelCurveProp = mPropertyProvider.getProperty("Pointer Accel Curve"); + accelCurveProp.setRealValues( + createAccelerationCurveForSensitivity(config->touchpadPointerSpeed, + accelCurveProp.getCount())); mPropertyProvider.getProperty("Invert Scrolling") .setBoolValues({config->touchpadNaturalScrollingEnabled}); mPropertyProvider.getProperty("Tap Enable") |