OmaPhoto 1.0.0: the Linux port of Compositor

A layered image editor for Linux and Omarchy, ported from Compositor
(github.com/robbietilton/Compositor), whose Swift source is its
specification. It reads and writes Compositor's .comp projects.

Packages for Ubuntu, Fedora and Arch come from the release workflow;
scripts/install/ holds one install script per distribution family,
and flake.nix serves NixOS.

Co-Authored-By: Claude <noreply@anthropic.com>

src/Document/CanvasSize.cpp

@@ -0,0 +1,75 @@
+#include "Document/CanvasSize.h"
+#include <cmath>
+
+QString rawValue(CanvasUnit unit)
+{
+    switch (unit) {
+    case CanvasUnit::pixels:
+        return QStringLiteral("Pixels");
+    case CanvasUnit::percent:
+        return QStringLiteral("Percent");
+    case CanvasUnit::inches:
+        return QStringLiteral("Inches");
+    case CanvasUnit::centimeters:
+        return QStringLiteral("Centimeters");
+    }
+    Q_UNREACHABLE();
+}
+
+CanvasSizeDraft::CanvasSizeDraft(qint64 width, qint64 height, double resolution)
+    : originalWidth(width), originalHeight(height), resolution(resolution), width(double(width)), height(double(height))
+{
+}
+
+bool CanvasSizeDraft::valid() const
+{
+    // NaN and infinity fail both range tests.
+    return std::round(width) >= 1 && std::round(width) <= 30'000 && std::round(height) >= 1 && std::round(height) <= 30'000;
+}
+
+double CanvasSizeDraft::displayed(bool widthAxis) const
+{
+    const double original = double(widthAxis ? originalWidth : originalHeight);
+    const double pixels = (widthAxis ? width : height) - (relative ? original : 0);
+    switch (unit) {
+    case CanvasUnit::pixels:
+        return pixels;
+    case CanvasUnit::percent:
+        return pixels / original * 100;
+    case CanvasUnit::inches:
+        return pixels / resolution;
+    case CanvasUnit::centimeters:
+        return pixels / resolution * 2.54;
+    }
+    Q_UNREACHABLE();
+}
+
+void CanvasSizeDraft::set(double value, bool widthAxis)
+{
+    const double original = double(widthAxis ? originalWidth : originalHeight);
+    double pixels = value;
+    if (unit == CanvasUnit::percent)
+        pixels = value / 100 * original;
+    else if (unit == CanvasUnit::inches)
+        pixels = value * resolution;
+    else if (unit == CanvasUnit::centimeters)
+        pixels = value / 2.54 * resolution;
+    const double total = pixels + (relative ? original : 0);
+    if (widthAxis) {
+        width = total;
+        if (locked)
+            height = total * double(originalHeight) / double(originalWidth);
+    } else {
+        height = total;
+        if (locked)
+            width = total * double(originalWidth) / double(originalHeight);
+    }
+}
+
+QPointF CanvasSizeOptions::offset(qint64 fromWidth, qint64 oldHeight) const
+{
+    if (contentOffset)
+        return *contentOffset;
+    // Floor: growth lands right and bottom, cuts left and top.
+    return QPointF(std::floor(double(width - fromWidth) * double(anchor % 3) / 2), std::floor(double(height - oldHeight) * double(anchor / 3) / 2));
+}