Add artifact related functions

This makes it possible to blend images with user configurable percent
(see `set_image_artifact` documentation)

src/types/mod.rs

@@ -15,6 +15,7 @@ mod pixel_interpolate_method;
 mod rendering_intent;
 mod resolution_type;
 mod resource_type;
+mod statistic_type;
 
 pub use self::alpha_channel_option::AlphaChannelOption;
 pub use self::colorspace_type::ColorspaceType;
@@ -33,3 +34,4 @@ pub use self::pixel_interpolate_method::PixelInterpolateMethod;
 pub use self::rendering_intent::RenderingIntent;
 pub use self::resolution_type::ResolutionType;
 pub use self::resource_type::ResourceType;
+pub use self::statistic_type::StatisticType;

src/types/statistic_type.rs

@@ -0,0 +1,46 @@
+use crate::bindings;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(u32)]
+pub enum StatisticType {
+    Undefined         = bindings::StatisticType_UndefinedStatistic,
+    Gradient          = bindings::StatisticType_GradientStatistic,
+    Maximum           = bindings::StatisticType_MaximumStatistic,
+    Mean              = bindings::StatisticType_MeanStatistic,
+    Median            = bindings::StatisticType_MedianStatistic,
+    Minimum           = bindings::StatisticType_MinimumStatistic,
+    Mode              = bindings::StatisticType_ModeStatistic,
+    Nonpeak           = bindings::StatisticType_NonpeakStatistic,
+    RootMeanSquare    = bindings::StatisticType_RootMeanSquareStatistic,
+    StandardDeviation = bindings::StatisticType_StandardDeviationStatistic,
+    Contrast          = bindings::StatisticType_ContrastStatistic,
+}
+
+impl Default for StatisticType {
+    fn default() -> Self {
+        return StatisticType::Undefined;
+    }
+}
+
+impl From<StatisticType> for bindings::StatisticType {
+    fn from(value: StatisticType) -> Self {
+        return value as bindings::StatisticType;
+    }
+}
+
+impl From<bindings::StatisticType> for StatisticType {
+    fn from(value: bindings::StatisticType) -> Self {
+        /*
+         * SAFETY:
+         *
+         * `StatisticType` has the same repr as `bindings::StatisticType` - u32
+         *
+         * If `value` is less than Contrast than it is in the vaild range and can be safely
+         * reinterpreted as `StatisticType`
+         */
+        if value <= bindings::StatisticType_ContrastStatistic {
+            return unsafe { std::mem::transmute(value) };
+        }
+        return StatisticType::default();
+    }
+}