[graphics/krita/krita/6.0] plugins/filters/colorsfilters: Fix color adjustment curve input controls on open

Git commit 462a30e0a2cadd52a2983b1447335448b3d8d033 by Dmitry Kazakov, on behalf of Moritz Staudinger.
Committed on 27/07/2026 at 13:56.
Pushed by dkazakov into branch 'krita/6.0'.

Fix color adjustment curve input controls on open

setActiveChannel() does nothing if the reset channel is
the same as the current one, so we should resync explicitly.

Fixes #117

M  +7    -2    plugins/filters/colorsfilters/kis_multichannel_filter_base.cpp
M  +1    -0    plugins/filters/colorsfilters/kis_multichannel_filter_base.h

https://invent.kde.org/graphics/krita/-/commit/462a30e0a2cadd52a2983b1447335448b3d8d033

diff --git a/plugins/filters/colorsfilters/kis_multichannel_filter_base.cpp b/plugins/filters/colorsfilters/kis_multichannel_filter_base.cpp
index 29020ef2045..d967b5608b3 100644
--- a/plugins/filters/colorsfilters/kis_multichannel_filter_base.cpp
+++ b/plugins/filters/colorsfilters/kis_multichannel_filter_base.cpp
@@ -434,12 +434,11 @@ void KisMultiChannelConfigWidget::init() {
         m_histogram = new KisHistogram(m_dev, m_dev->exactBounds(), hpf->generate(), LINEAR);
     }
 
-    m_page->curveWidget->setCurve(m_curves[0]);
     connect(m_page->curveWidget, SIGNAL(modified()), this, SLOT(slotCurveModified()));
 
     {
         KisSignalsBlocker b(m_page->curveWidget);
-        setActiveChannel(0);
+        syncActiveChannelUi();
     }
 }
 
@@ -662,6 +661,12 @@ void KisMultiChannelConfigWidget::setActiveChannel(int ch)
     KIS_SAFE_ASSERT_RECOVER_RETURN(ch < m_curves.size());
 
     m_activeVChannel = ch;
+
+    syncActiveChannelUi();
+}
+
+void KisMultiChannelConfigWidget::syncActiveChannelUi()
+{
     m_page->curveWidget->setCurve(m_curves[m_activeVChannel]);
     m_page->curveWidget->setPixmap(getHistogram());
 
diff --git a/plugins/filters/colorsfilters/kis_multichannel_filter_base.h b/plugins/filters/colorsfilters/kis_multichannel_filter_base.h
index 3ed92844092..ba2be21c55a 100644
--- a/plugins/filters/colorsfilters/kis_multichannel_filter_base.h
+++ b/plugins/filters/colorsfilters/kis_multichannel_filter_base.h
@@ -127,6 +127,7 @@ protected:
     void init();
     void resetCurves();
     void setActiveChannel(int ch);
+    void syncActiveChannelUi();
     virtual int findDefaultVirtualChannelSelection();
 
     virtual void updateChannelControls() = 0;