| /* |
| * Copyright 2013 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "Daltonizer.h" |
| #include <math/mat4.h> |
| |
| namespace android { |
| |
| void Daltonizer::setType(ColorBlindnessType type) { |
| if (type != mType) { |
| mDirty = true; |
| mType = type; |
| } |
| } |
| |
| void Daltonizer::setMode(ColorBlindnessMode mode) { |
| if (mode != mMode) { |
| mDirty = true; |
| mMode = mode; |
| } |
| } |
| |
| const mat4& Daltonizer::operator()() { |
| if (mDirty) { |
| mDirty = false; |
| update(); |
| } |
| return mColorTransform; |
| } |
| |
| void Daltonizer::update() { |
| if (mType == ColorBlindnessType::None) { |
| mColorTransform = mat4(); |
| return; |
| } |
| |
| // converts a linear RGB color to the XYZ space |
| const mat4 rgb2xyz( 0.4124, 0.2126, 0.0193, 0, |
| 0.3576, 0.7152, 0.1192, 0, |
| 0.1805, 0.0722, 0.9505, 0, |
| 0 , 0 , 0 , 1); |
| |
| // converts a XYZ color to the LMS space. |
| const mat4 xyz2lms( 0.7328,-0.7036, 0.0030, 0, |
| 0.4296, 1.6975, 0.0136, 0, |
| -0.1624, 0.0061, 0.9834, 0, |
| 0 , 0 , 0 , 1); |
| |
| // Direct conversion from linear RGB to LMS |
| const mat4 rgb2lms(xyz2lms*rgb2xyz); |
| |
| // And back from LMS to linear RGB |
| const mat4 lms2rgb(inverse(rgb2lms)); |
| |
| // To simulate color blindness we need to "remove" the data lost by the absence of |
| // a cone. This cannot be done by just zeroing out the corresponding LMS component |
| // because it would create a color outside of the RGB gammut. |
| // Instead we project the color along the axis of the missing component onto a plane |
| // within the RGB gammut: |
| // - since the projection happens along the axis of the missing component, a |
| // color blind viewer perceives the projected color the same. |
| // - We use the plane defined by 3 points in LMS space: black, white and |
| // blue and red for protanopia/deuteranopia and tritanopia respectively. |
| |
| // LMS space red |
| const vec3& lms_r(rgb2lms[0].rgb); |
| // LMS space blue |
| const vec3& lms_b(rgb2lms[2].rgb); |
| // LMS space white |
| const vec3 lms_w((rgb2lms * vec4(1)).rgb); |
| |
| // To find the planes we solve the a*L + b*M + c*S = 0 equation for the LMS values |
| // of the three known points. This equation is trivially solved, and has for |
| // solution the following cross-products: |
| const vec3 p0 = cross(lms_w, lms_b); // protanopia/deuteranopia |
| const vec3 p1 = cross(lms_w, lms_r); // tritanopia |
| |
| // The following 3 matrices perform the projection of a LMS color onto the given plane |
| // along the selected axis |
| |
| // projection for protanopia (L = 0) |
| const mat4 lms2lmsp( 0.0000, 0.0000, 0.0000, 0, |
| -p0.y / p0.x, 1.0000, 0.0000, 0, |
| -p0.z / p0.x, 0.0000, 1.0000, 0, |
| 0 , 0 , 0 , 1); |
| |
| // projection for deuteranopia (M = 0) |
| const mat4 lms2lmsd( 1.0000, -p0.x / p0.y, 0.0000, 0, |
| 0.0000, 0.0000, 0.0000, 0, |
| 0.0000, -p0.z / p0.y, 1.0000, 0, |
| 0 , 0 , 0 , 1); |
| |
| // projection for tritanopia (S = 0) |
| const mat4 lms2lmst( 1.0000, 0.0000, -p1.x / p1.z, 0, |
| 0.0000, 1.0000, -p1.y / p1.z, 0, |
| 0.0000, 0.0000, 0.0000, 0, |
| 0 , 0 , 0 , 1); |
| |
| // We will calculate the error between the color and the color viewed by |
| // a color blind user and "spread" this error onto the healthy cones. |
| // The matrices below perform this last step and have been chosen arbitrarily. |
| |
| // The amount of correction can be adjusted here. |
| |
| // error spread for protanopia |
| const mat4 errp( 1.0, 0.7, 0.7, 0, |
| 0.0, 1.0, 0.0, 0, |
| 0.0, 0.0, 1.0, 0, |
| 0, 0, 0, 1); |
| |
| // error spread for deuteranopia |
| const mat4 errd( 1.0, 0.0, 0.0, 0, |
| 0.7, 1.0, 0.7, 0, |
| 0.0, 0.0, 1.0, 0, |
| 0, 0, 0, 1); |
| |
| // error spread for tritanopia |
| const mat4 errt( 1.0, 0.0, 0.0, 0, |
| 0.0, 1.0, 0.0, 0, |
| 0.7, 0.7, 1.0, 0, |
| 0, 0, 0, 1); |
| |
| // And the magic happens here... |
| // We construct the matrix that will perform the whole correction. |
| |
| // simulation: type of color blindness to simulate: |
| // set to either lms2lmsp, lms2lmsd, lms2lmst |
| mat4 simulation; |
| |
| // correction: type of color blindness correction (should match the simulation above): |
| // set to identity, errp, errd, errt ([0] for simulation only) |
| mat4 correction(0); |
| |
| switch (mType) { |
| case ColorBlindnessType::Protanomaly: |
| simulation = lms2lmsp; |
| if (mMode == ColorBlindnessMode::Correction) |
| correction = errp; |
| break; |
| case ColorBlindnessType::Deuteranomaly: |
| simulation = lms2lmsd; |
| if (mMode == ColorBlindnessMode::Correction) |
| correction = errd; |
| break; |
| case ColorBlindnessType::Tritanomaly: |
| simulation = lms2lmst; |
| if (mMode == ColorBlindnessMode::Correction) |
| correction = errt; |
| break; |
| case ColorBlindnessType::None: |
| // We already caught this at the beginning of the method, but the |
| // compiler doesn't know that |
| break; |
| } |
| |
| mColorTransform = lms2rgb * |
| (simulation * rgb2lms + correction * (rgb2lms - simulation * rgb2lms)); |
| } |
| |
| } /* namespace android */ |