color blindness enhancement
This is an attempt at improving the experience of
users with color vision impairement.
At this time this feature can only be enabled for
debugging:
adb shell service call SurfaceFlinger 1014 i32 PARAM
with PARAM:
0 : disabled
1 : protanomaly/protanopia simulation
2 : deuteranomaly/deuteranopia simulation
3 : tritanopia/tritanomaly simulation
11, 12, 13: same as above w/ attempted correction/enhancement
The enhancement algorithm tries to spread the "error"
such that tones that would otherwise appear similar can be
distinguished.
Bug: 9465644
Change-Id: I860f7eed0cb81f54ef9cf24ad78155b6395ade48
diff --git a/services/surfaceflinger/Effects/Daltonizer.cpp b/services/surfaceflinger/Effects/Daltonizer.cpp
new file mode 100644
index 0000000..f384ba4
--- /dev/null
+++ b/services/surfaceflinger/Effects/Daltonizer.cpp
@@ -0,0 +1,183 @@
+/*
+ * 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 <ui/mat4.h>
+
+namespace android {
+
+Daltonizer::Daltonizer() :
+ mType(deuteranomaly), mMode(simulation), mDirty(true) {
+}
+
+Daltonizer::~Daltonizer() {
+}
+
+void Daltonizer::setType(Daltonizer::ColorBlindnessTypes type) {
+ if (type != mType) {
+ mDirty = true;
+ mType = type;
+ }
+}
+
+void Daltonizer::setMode(Daltonizer::Mode mode) {
+ if (mode != mMode) {
+ mDirty = true;
+ mMode = mode;
+ }
+}
+
+const mat4& Daltonizer::operator()() {
+ if (mDirty) {
+ mDirty = false;
+ update();
+ }
+ return mColorTransform;
+}
+
+void Daltonizer::update() {
+ // 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);
+
+ const mat4 identity;
+
+ // 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);
+
+ // control: simulation post-correction (used for debugging):
+ // set to identity or lms2lmsp, lms2lmsd, lms2lmst
+ mat4 control;
+ switch (mType) {
+ case protanopia:
+ case protanomaly:
+ simulation = lms2lmsp;
+ if (mMode == Daltonizer::correction)
+ correction = errp;
+ break;
+ case deuteranopia:
+ case deuteranomaly:
+ simulation = lms2lmsd;
+ if (mMode == Daltonizer::correction)
+ correction = errd;
+ break;
+ case tritanopia:
+ case tritanomaly:
+ simulation = lms2lmst;
+ if (mMode == Daltonizer::correction)
+ correction = errt;
+ break;
+ }
+
+ if (true) {
+ control = simulation;
+ }
+
+ mColorTransform = lms2rgb * control *
+ (simulation * rgb2lms + correction * (rgb2lms - simulation * rgb2lms));
+}
+
+} /* namespace android */