[GUI] Color slider update and fixes

app/app.pro

@@ -79,6 +79,7 @@ HEADERS += \
     src/basewidget.h \
     src/appearance.h \
     src/buttonappearancewatcher.h \
+    src/colorpreviewwidget.h \
     src/importlayersdialog.h \
     src/importpositiondialog.h \
     src/layeropacitydialog.h \
@@ -136,6 +137,7 @@ SOURCES += \
     src/addtransparencytopaperdialog.cpp \
     src/basewidget.cpp \
     src/buttonappearancewatcher.cpp \
+    src/colorpreviewwidget.cpp \
     src/importlayersdialog.cpp \
     src/importpositiondialog.cpp \
     src/layeropacitydialog.cpp \

app/src/colorinspector.cpp

@@ -56,23 +56,15 @@ void ColorInspector::initUI()
     }
     onColorSpecChanged();
 
-    ui->redSlider->init(ColorSlider::ColorSpecType::RGB, ColorSlider::ColorType::RED, mCurrentColor, 0.0, 255.0);
-    ui->greenSlider->init(ColorSlider::ColorSpecType::RGB, ColorSlider::ColorType::GREEN, mCurrentColor, 0.0, 255.0);
-    ui->blueSlider->init(ColorSlider::ColorSpecType::RGB, ColorSlider::ColorType::BLUE, mCurrentColor, 0.0, 255.0);
-    ui->rgbAlphaSlider->init(ColorSlider::ColorSpecType::RGB, ColorSlider::ColorType::ALPHA, mCurrentColor, 0.0, 255.0);
+    ui->redSlider->init(ColorSlider::ColorSpecType::RGB, ColorSlider::ColorType::RED, mCurrentColor);
+    ui->greenSlider->init(ColorSlider::ColorSpecType::RGB, ColorSlider::ColorType::GREEN, mCurrentColor);
+    ui->blueSlider->init(ColorSlider::ColorSpecType::RGB, ColorSlider::ColorType::BLUE, mCurrentColor);
+    ui->rgbAlphaSlider->init(ColorSlider::ColorSpecType::RGB, ColorSlider::ColorType::ALPHA, mCurrentColor);
 
-    ui->hueSlider->init(ColorSlider::ColorSpecType::HSV, ColorSlider::ColorType::HUE, mCurrentColor, 0.0, 359.0);
-    ui->saturationSlider->init(ColorSlider::ColorSpecType::HSV, ColorSlider::ColorType::SAT, mCurrentColor, 0.0, 255.0);
-    ui->valueSlider->init(ColorSlider::ColorSpecType::HSV, ColorSlider::ColorType::VAL, mCurrentColor, 0.0, 255.0);
-    ui->hsvAlphaSlider->init(ColorSlider::ColorSpecType::HSV, ColorSlider::ColorType::ALPHA, mCurrentColor, 0.0, 255.0);
-
-    QPalette p1 = ui->colorWrapper->palette();
-    p1.setBrush(QPalette::Window, QBrush(QImage(":/background/checkerboard.png")));
-    ui->colorWrapper->setPalette(p1);
-
-    QPalette p2 = ui->color->palette();
-    p2.setColor(QPalette::Window, mCurrentColor);
-    ui->color->setPalette(p2);
+    ui->hueSlider->init(ColorSlider::ColorSpecType::HSV, ColorSlider::ColorType::HUE, mCurrentColor);
+    ui->saturationSlider->init(ColorSlider::ColorSpecType::HSV, ColorSlider::ColorType::SAT, mCurrentColor);
+    ui->valueSlider->init(ColorSlider::ColorSpecType::HSV, ColorSlider::ColorType::VAL, mCurrentColor);
+    ui->hsvAlphaSlider->init(ColorSlider::ColorSpecType::HSV, ColorSlider::ColorType::ALPHA, mCurrentColor);
 
     connect(ui->colorSpecTabWidget, &QTabWidget::currentChanged, this, &ColorInspector::onColorSpecChanged);
 
@@ -179,9 +171,8 @@ void ColorInspector::updateControls()
     ui->valueSpinBox->setValue(qRound(mCurrentColor.value() / 2.55));
     ui->hsvAlphaSpinBox->setValue(qRound(mCurrentColor.alpha() / 2.55));
 
-    QPalette p = ui->color->palette();
-    p.setColor(QPalette::Window, mCurrentColor);
-    ui->color->setPalette(p);
+
+    ui->colorPreview->setColor(mCurrentColor);
 
     update();
 }
@@ -200,7 +191,9 @@ void ColorInspector::onColorSpecChanged()
     }
     else
     {
-        mCurrentColor = mCurrentColor.toHsv();
+        if (mCurrentColor.hue() != -1) {
+            mCurrentColor = mCurrentColor.toHsv();
+        }
     }
 
     updateControls();

app/src/colorpreviewwidget.cpp

@@ -0,0 +1,43 @@
+/*
+
+Pencil2D - Traditional Animation Software
+Copyright (C) 2026 Oliver Stevns Larsen
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+*/
+#include "colorpreviewwidget.h"
+
+#include <QPainter>
+#include <QPaintEvent>
+
+ColorPreviewWidget::ColorPreviewWidget(QWidget*)
+{
+
+}
+
+void ColorPreviewWidget::setColor(const QColor& color)
+{
+    if (color == mColor) { return; }
+
+    mColor = color;
+    update();
+}
+
+void ColorPreviewWidget::paintEvent(QPaintEvent* event)
+{
+    QPainter painter(this);
+
+    painter.setPen(Qt::NoPen);
+    painter.setBrush(QBrush(mCheckerboard));
+    painter.drawRect(event->rect());
+
+    painter.fillRect(event->rect(), mColor);
+}

app/src/colorpreviewwidget.h

@@ -0,0 +1,41 @@
+/*
+
+Pencil2D - Traditional Animation Software
+Copyright (C) 2026 Oliver Stevns Larsen
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+*/
+#ifndef COLORPREVIEWWIDGET_H
+#define COLORPREVIEWWIDGET_H
+
+#include <QObject>
+#include <QWidget>
+
+class ColorPreviewWidget: public QWidget
+{
+    Q_OBJECT
+public:
+    explicit ColorPreviewWidget(QWidget* = nullptr);
+
+    void setColor(const QColor& color);
+
+protected:
+     void paintEvent(QPaintEvent* event) override;
+
+private:
+
+     QPixmap mColorPreviewPixmap;
+     QPixmap mCheckerboard = QPixmap(":/background/checkerboard.png");
+
+     QColor mColor;
+};
+
+#endif // COLORPREVIEWWIDGET_H