From 4f9cd7a11fc2b352b8db038237c7b137fa8f9a25 Mon Sep 17 00:00:00 2001
From: Mateusz Grzywacz <mateusz.grzywacz@mudita.com>
Date: Mon, 25 Jan 2021 17:01:20 +0100
Subject: [PATCH] [EGD-5394] Eink - reuse temperature for waveforms

Do not waste time right before refresh of the eink
display to measure new temperature. Assume that
the measurement from early frame prepare stage is valid.
It has only to be valid for only <time of rendering the frame>,
which is less than a 1000ms.
---
 module-services/service-eink/EinkDisplay.cpp |  5 +++++
 module-services/service-eink/EinkDisplay.hpp |  1 +
 module-services/service-eink/ServiceEink.cpp | 11 ++++++-----
 module-services/service-eink/ServiceEink.hpp | 10 +++++++++-
 4 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/module-services/service-eink/EinkDisplay.cpp b/module-services/service-eink/EinkDisplay.cpp
index b6812757f8f6299a453fa0d195a5aa6e2023b648..ec8a6ec61f87c2edc09efb02b021ad39f601fd75 100644
--- a/module-services/service-eink/EinkDisplay.cpp
+++ b/module-services/service-eink/EinkDisplay.cpp
@@ -232,6 +232,11 @@ namespace service::eink
         displayMode = mode;
     }
 
+    std::int32_t EinkDisplay::getLastTemperature() const noexcept
+    {
+        return currentWaveform.temperature;
+    }
+
     ::gui::Size EinkDisplay::getSize() const noexcept
     {
         return size;
diff --git a/module-services/service-eink/EinkDisplay.hpp b/module-services/service-eink/EinkDisplay.hpp
index 80ae6859e9d8be4739061351d5ce7e8ebc3b3356..4f61bba6eaeba5412501441a2ba652de63d1a3d9 100644
--- a/module-services/service-eink/EinkDisplay.hpp
+++ b/module-services/service-eink/EinkDisplay.hpp
@@ -35,6 +35,7 @@ namespace service::eink
         bool setWaveform(EinkWaveforms_e mode, std::int32_t temperature);
         void setMode(EinkDisplayColorMode_e mode) noexcept;
 
+        std::int32_t getLastTemperature() const noexcept;
         ::gui::Size getSize() const noexcept;
 
       private:
diff --git a/module-services/service-eink/ServiceEink.cpp b/module-services/service-eink/ServiceEink.cpp
index 8cd43671aceb1ffd6c3727351c2dc245e8a36ccd..112a691005ed0e4efd92163b923f61fdc598803e 100644
--- a/module-services/service-eink/ServiceEink.cpp
+++ b/module-services/service-eink/ServiceEink.cpp
@@ -1,4 +1,4 @@
-// Copyright (c) 2017-2020, Mudita Sp. z.o.o. All rights reserved.
+// Copyright (c) 2017-2021, Mudita Sp. z.o.o. All rights reserved.
 // For licensing, see https://github.com/mudita/MuditaOS/LICENSE.md
 
 #include "ServiceEink.hpp"
@@ -121,7 +121,7 @@ namespace service::eink
 
     void ServiceEink::updateDisplay(std::uint8_t *frameBuffer, ::gui::RefreshModes refreshMode)
     {
-        prepareDisplay(refreshMode);
+        prepareDisplay(refreshMode, WaveformTemperature::KEEP_CURRENT);
 
         if (const auto status = display.update(frameBuffer); status != EinkOK) {
             LOG_FATAL("Failed to update frame");
@@ -135,11 +135,12 @@ namespace service::eink
         }
     }
 
-    void ServiceEink::prepareDisplay(::gui::RefreshModes refreshMode)
+    void ServiceEink::prepareDisplay(::gui::RefreshModes refreshMode, WaveformTemperature behaviour)
     {
         display.powerOn();
 
-        const auto temperature = EinkGetTemperatureInternal();
+        const auto temperature = behaviour == WaveformTemperature::KEEP_CURRENT ? display.getLastTemperature()
+                                                                                : EinkGetTemperatureInternal();
         if (refreshMode == ::gui::RefreshModes::GUI_REFRESH_DEEP) {
             display.setWaveform(EinkWaveforms_e::EinkWaveformGC16, temperature);
             display.dither();
@@ -152,7 +153,7 @@ namespace service::eink
     sys::MessagePointer ServiceEink::handlePrepareEarlyRequest(sys::Message *message)
     {
         const auto waveformUpdateMsg = static_cast<service::eink::PrepareDisplayEarlyRequest *>(message);
-        prepareDisplay(waveformUpdateMsg->getRefreshMode());
+        prepareDisplay(waveformUpdateMsg->getRefreshMode(), WaveformTemperature::MEASURE_NEW);
         return sys::MessageNone{};
     }
 
diff --git a/module-services/service-eink/ServiceEink.hpp b/module-services/service-eink/ServiceEink.hpp
index 607def849ad25d708852333c1752ce668be50ccf..b7e139f97ed247efd55c3eb3345095c5778e75a2 100644
--- a/module-services/service-eink/ServiceEink.hpp
+++ b/module-services/service-eink/ServiceEink.hpp
@@ -31,13 +31,21 @@ namespace service::eink
             Running,
             Suspended
         };
+
+        /// It takes 25ms to get a new measurement
+        enum class WaveformTemperature
+        {
+            KEEP_CURRENT,
+            MEASURE_NEW,
+        };
+
         void setState(State state) noexcept;
         bool isInState(State state) const noexcept;
 
         void enterActiveMode();
         void suspend();
         void updateDisplay(std::uint8_t *frameBuffer, ::gui::RefreshModes refreshMode);
-        void prepareDisplay(::gui::RefreshModes refreshMode);
+        void prepareDisplay(::gui::RefreshModes refreshMode, WaveformTemperature behaviour);
 
         sys::MessagePointer handleEinkModeChangedMessage(sys::Message *message);
         sys::MessagePointer handleImageMessage(sys::Message *message);