The document's own pixel budget, marching ants at screen resolution (12.11a)

tests/BudgetFixtures.h

@@ -0,0 +1,26 @@
+#pragma once
+#include "Document/BrushStroke.h"
+#include "Document/DocumentLimits.h"
+#include "Rendering/RasterSnapshot.h"
+#include <vector>
+
+// A layer claiming its size in pixels, holding one.
+inline ImportedImage claimed(int width, int height, const QString &name = QStringLiteral("Claimed"))
+{
+    const auto raster = std::make_shared<const RasterSnapshot>(width, height, BrushRaster::context(1, 1, false), QRectF(0, 0, width, height),
+                                                               std::vector<BrushPatch>{});
+    return ImportedImage(raster, QImage(), name);
+}
+
+// Layers claiming `pixels` in all, each within one surface.
+inline std::vector<ImportedImage> claiming(qint64 pixels)
+{
+    std::vector<ImportedImage> layers;
+    const int side = DocumentLimits::maxSide;
+    while (pixels > 0) {
+        const qint64 rows = std::min<qint64>(pixels / side, DocumentLimits::maxSurfacePixels / side);
+        layers.push_back(rows > 0 ? claimed(side, int(rows)) : claimed(int(pixels), 1));
+        pixels -= rows > 0 ? side * rows : pixels;
+    }
+    return layers;
+}