From 5e17a8f61cf1684a6201163038be2ed13f58a3c9 Mon Sep 17 00:00:00 2001
From: Filip Leonarski <filip.leonarski@psi.ch>
Date: Sun, 1 Feb 2026 11:53:56 +0100
Subject: [PATCH] jfjoch_viewer: Use multiple threads to color images

---
 viewer/CMakeLists.txt               |  4 ++--
 viewer/image_viewer/JFJochImage.cpp | 10 ++++++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/viewer/CMakeLists.txt b/viewer/CMakeLists.txt
index 4587d32a..103f53f4 100644
--- a/viewer/CMakeLists.txt
+++ b/viewer/CMakeLists.txt
@@ -5,7 +5,7 @@ SET(CMAKE_AUTOMOC ON)
 SET(CMAKE_AUTORCC ON)
 SET(CMAKE_AUTOUIC ON)
 
-FIND_PACKAGE(Qt6 COMPONENTS Core Gui Widgets Charts DBus REQUIRED)
+FIND_PACKAGE(Qt6 COMPONENTS Core Gui Widgets Charts DBus Concurrent REQUIRED)
 
 QT_ADD_RESOURCES(APP_RESOURCES resources/resources.qrc)
 
@@ -86,7 +86,7 @@ ADD_EXECUTABLE(jfjoch_viewer jfjoch_viewer.cpp JFJochViewerWindow.cpp JFJochView
         ${APP_RESOURCES}
 )
 
-TARGET_LINK_LIBRARIES(jfjoch_viewer Qt6::Core Qt6::Gui Qt6::Widgets Qt6::Charts Qt6::DBus
+TARGET_LINK_LIBRARIES(jfjoch_viewer Qt6::Core Qt6::Gui Qt6::Widgets Qt6::Charts Qt6::DBus Qt6::Concurrent
         JFJochReader JFJochLogger JFJochCommon JFJochWriter JFJochImageAnalysis)
 INSTALL(TARGETS jfjoch_viewer RUNTIME COMPONENT viewer)
 
diff --git a/viewer/image_viewer/JFJochImage.cpp b/viewer/image_viewer/JFJochImage.cpp
index 4f470552..4efa71aa 100644
--- a/viewer/image_viewer/JFJochImage.cpp
+++ b/viewer/image_viewer/JFJochImage.cpp
@@ -16,6 +16,7 @@
 #include <QBuffer>
 #include <QElapsedTimer>
 #include <QPainter>
+#include <QtConcurrent/QtConcurrent>
 
 JFJochImage::JFJochImage(QWidget *parent) : QGraphicsView(parent) {
     setDragMode(QGraphicsView::NoDrag); // Disable default drag mode
@@ -614,7 +615,12 @@ void JFJochImage::GeneratePixmap() {
     const float invRangeLog = (range > 0) ? (lutScale / std::log1p(range)) : 0.0f;
 
     rgb gap_color = color_scale.Apply(ColorScaleSpecial::Gap);
-    for (int y = 0; y < H; ++y) {
+
+    QVector<int> rows;
+    rows.reserve(H);
+    for (int y = 0; y < H; ++y) rows.push_back(y);
+
+    QtConcurrent::blockingMap(rows, [&](int y) {
         QRgb *scanLine = reinterpret_cast<QRgb*>(qimg.scanLine(y));
         const float *row = &image_fp[y * W];
         rgb *out = &image_rgb[y * W];
@@ -654,7 +660,7 @@ void JFJochImage::GeneratePixmap() {
             out[x] = c;
             scanLine[x] = qRgb(c.r, c.g, c.b);
         }
-    }
+    });
 
     pixmap = QPixmap::fromImage(qimg);
     pixmap.setDevicePixelRatio(1.0);