diff -r 94b0a30a1886 -r da4876bfd822 widgets/multiplyfactordialog.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widgets/multiplyfactordialog.cpp	Wed Jun 22 20:27:53 2022 +0300
@@ -0,0 +1,102 @@
+#include "multiplyfactordialog.h"
+#include "ui_multiplyfactordialog.h"
+
+MultiplyFactorDialog::MultiplyFactorDialog(const glm::vec3& baseVector, QWidget* parent) :
+	QDialog{parent},
+	baseVector{baseVector},
+	preview{baseVector, parent, Vec3Editor::NoMultiplyButton}
+{
+	ui = std::make_unique<Ui::MultiplyFactorDialog>();
+	ui->setupUi(this);
+	this->preview.setEnabled(false);
+	this->ui->previewGroupBox->setLayout(new QVBoxLayout{parent});
+	this->ui->previewGroupBox->layout()->addWidget(&this->preview);
+	connect(
+		this->ui->invert,
+		&QCheckBox::clicked,
+		this,
+		&MultiplyFactorDialog::updatePreview);
+	connect(
+		this->ui->factor,
+		qOverload<double>(&DoubleSpinBox::valueChanged),
+		this,
+		&MultiplyFactorDialog::updatePreview);
+}
+
+/**
+ * @brief empty destructor, necessary because std::unique_ptr is used with a forward declaration
+ */
+MultiplyFactorDialog::~MultiplyFactorDialog()
+{
+}
+
+/**
+ * @brief Computes the resulting vector
+ * @return the input vector multiplied by the specified vector
+ */
+glm::vec3 MultiplyFactorDialog::value() const
+{
+	glm::vec3 result = baseVector;
+	if (this->ui->invert->isChecked())
+	{
+		if (qFuzzyIsNull(this->ui->factor->value()))
+		{
+			constexpr double infinity = std::numeric_limits<double>::quiet_NaN();
+			result = {infinity, infinity, infinity};
+		}
+		else
+		{
+			result /= this->ui->factor->value();
+		}
+	}
+	else
+	{
+		result *= this->ui->factor->value();
+	}
+	return result;
+}
+
+/**
+ * @brief Makes a string that is prefixed to the factor input.
+ * @param ui
+ * @return prefix string
+ */
+QString prefixForFactorInput(const Ui::MultiplyFactorDialog& ui)
+{
+	if (ui.invert->isChecked())
+	{
+		return "1 : ";
+	}
+	else
+	{
+		return "";
+	}
+}
+
+/**
+ * @brief Makes a string that is suffixed to the factor input.
+ * @param ui
+ * @return prefix string
+ */
+QString suffixForFactorInput(const Ui::MultiplyFactorDialog& ui)
+{
+	if (ui.invert->isChecked())
+	{
+		// render the actual factor that stuff gets effectively multiplied by
+		return " = " + QString::number(1.0 / (ui.factor->value()));
+	}
+	else
+	{
+		return "";
+	}
+}
+
+/**
+ * @brief Responds to changes in the value and updates previews accordingly
+ */
+void MultiplyFactorDialog::updatePreview()
+{
+	this->ui->factor->setPrefix(::prefixForFactorInput(*this->ui));
+	this->ui->factor->setSuffix(::suffixForFactorInput(*this->ui));
+	this->preview.setValue(this->value());
+}