Add paint brush parameter tests

src/paint/brush.cpp

@@ -0,0 +1,72 @@
+#include "paint/brush.h"
+
+#include <algorithm>
+#include <cmath>
+
+namespace pp::paint {
+
+namespace {
+
+[[nodiscard]] bool finite_in_range(float value, float min, float max) noexcept
+{
+    return std::isfinite(value) && value >= min && value <= max;
+}
+
+[[nodiscard]] float clamp01(float value) noexcept
+{
+    return std::clamp(value, 0.0F, 1.0F);
+}
+
+}
+
+pp::foundation::Status validate_brush_params(const BrushParams& params) noexcept
+{
+    if (!finite_in_range(params.size, min_brush_size, max_brush_size)) {
+        return pp::foundation::Status::out_of_range("brush size is outside the configured range");
+    }
+
+    if (!finite_in_range(params.spacing, min_brush_spacing, max_brush_spacing)) {
+        return pp::foundation::Status::out_of_range("brush spacing is outside the configured range");
+    }
+
+    if (!finite_in_range(params.opacity, 0.0F, 1.0F)) {
+        return pp::foundation::Status::out_of_range("brush opacity must be finite and within 0..1");
+    }
+
+    if (!finite_in_range(params.flow, 0.0F, 1.0F)) {
+        return pp::foundation::Status::out_of_range("brush flow must be finite and within 0..1");
+    }
+
+    if (!finite_in_range(params.angle_degrees, -max_brush_angle_degrees, max_brush_angle_degrees)) {
+        return pp::foundation::Status::out_of_range("brush angle is outside the configured range");
+    }
+
+    if (!finite_in_range(params.size_jitter, 0.0F, 1.0F)) {
+        return pp::foundation::Status::out_of_range("brush size jitter must be finite and within 0..1");
+    }
+
+    if (!finite_in_range(params.opacity_jitter, 0.0F, 1.0F)) {
+        return pp::foundation::Status::out_of_range("brush opacity jitter must be finite and within 0..1");
+    }
+
+    return pp::foundation::Status::success();
+}
+
+BrushStamp evaluate_brush_stamp(const BrushParams& params, float pressure) noexcept
+{
+    const auto clamped_pressure = clamp01(std::isfinite(pressure) ? pressure : 0.0F);
+    const auto size_pressure = params.pressure_controls_size ? clamped_pressure : 1.0F;
+    const auto opacity_pressure = params.pressure_controls_opacity ? clamped_pressure : 1.0F;
+
+    const auto jitter_size_scale = 1.0F - (params.size_jitter * 0.5F);
+    const auto jitter_opacity_scale = 1.0F - (params.opacity_jitter * 0.5F);
+
+    return BrushStamp {
+        .size = std::max(min_brush_size, params.size * size_pressure * jitter_size_scale),
+        .opacity = clamp01(params.opacity * opacity_pressure * jitter_opacity_scale),
+        .flow = clamp01(params.flow),
+        .angle_degrees = params.angle_degrees,
+    };
+}
+
+}

src/paint/brush.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include "foundation/result.h"
+
+#include <cstdint>
+
+namespace pp::paint {
+
+constexpr float min_brush_size = 0.1F;
+constexpr float max_brush_size = 4096.0F;
+constexpr float min_brush_spacing = 0.01F;
+constexpr float max_brush_spacing = 16.0F;
+constexpr float max_brush_angle_degrees = 360.0F;
+
+struct BrushParams {
+    float size = 32.0F;
+    float spacing = 0.25F;
+    float opacity = 1.0F;
+    float flow = 1.0F;
+    float angle_degrees = 0.0F;
+    float size_jitter = 0.0F;
+    float opacity_jitter = 0.0F;
+    bool pressure_controls_size = true;
+    bool pressure_controls_opacity = false;
+};
+
+struct BrushStamp {
+    float size = 0.0F;
+    float opacity = 0.0F;
+    float flow = 0.0F;
+    float angle_degrees = 0.0F;
+};
+
+[[nodiscard]] pp::foundation::Status validate_brush_params(const BrushParams& params) noexcept;
+[[nodiscard]] BrushStamp evaluate_brush_stamp(const BrushParams& params, float pressure) noexcept;
+
+}