Add AlphaChannelOption type

src/types/alpha_channel_option.rs

@@ -0,0 +1,52 @@
+use crate::bindings;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(u32)]
+pub enum AlphaChannelOption {
+    Undefined    = bindings::AlphaChannelOption_UndefinedAlphaChannel,
+    Activate     = bindings::AlphaChannelOption_ActivateAlphaChannel,
+    Associate    = bindings::AlphaChannelOption_AssociateAlphaChannel,
+    Background   = bindings::AlphaChannelOption_BackgroundAlphaChannel,
+    Copy         = bindings::AlphaChannelOption_CopyAlphaChannel,
+    Deactivate   = bindings::AlphaChannelOption_DeactivateAlphaChannel,
+    Discrete     = bindings::AlphaChannelOption_DiscreteAlphaChannel,
+    Disassociate = bindings::AlphaChannelOption_DisassociateAlphaChannel,
+    Extract      = bindings::AlphaChannelOption_ExtractAlphaChannel,
+    Off          = bindings::AlphaChannelOption_OffAlphaChannel,
+    On           = bindings::AlphaChannelOption_OnAlphaChannel,
+    Opaque       = bindings::AlphaChannelOption_OpaqueAlphaChannel,
+    Remove       = bindings::AlphaChannelOption_RemoveAlphaChannel,
+    Set          = bindings::AlphaChannelOption_SetAlphaChannel,
+    Shape        = bindings::AlphaChannelOption_ShapeAlphaChannel,
+    Transparent  = bindings::AlphaChannelOption_TransparentAlphaChannel,
+    OffIfOpaque  = bindings::AlphaChannelOption_OffIfOpaqueAlphaChannel,
+}
+
+impl Default for AlphaChannelOption {
+    fn default() -> Self {
+        return AlphaChannelOption::Undefined;
+    }
+}
+
+impl From<AlphaChannelOption> for bindings::AlphaChannelOption {
+    fn from(value: AlphaChannelOption) -> Self {
+        return value as bindings::AlphaChannelOption;
+    }
+}
+
+impl From<bindings::AlphaChannelOption> for AlphaChannelOption {
+    fn from(value: bindings::AlphaChannelOption) -> Self {
+        /*
+         * SAFETY:
+         *
+         * `AlphaChannelOption` has the same repr as `bindings::AlphaChannelOption` - u32
+         *
+         * If `value` is less than OffIfOpaque than it is in the vaild range and can be safely
+         * reinterpreted as `AlphaChannelOption`
+         */
+        if value <= bindings::AlphaChannelOption_OffIfOpaqueAlphaChannel {
+            return unsafe { std::mem::transmute(value) };
+        }
+        return AlphaChannelOption::default();
+    }
+}

src/types/mod.rs

@@ -1,3 +1,4 @@
+mod alpha_channel_option;
 mod colorspace_type;
 mod composite_operator;
 mod dither_method;
@@ -7,6 +8,7 @@ mod pixel_interpolate_method;
 mod metric_type;
 mod resource_type;
 
+pub use self::alpha_channel_option::AlphaChannelOption;
 pub use self::colorspace_type::ColorspaceType;
 pub use self::composite_operator::CompositeOperator;
 pub use self::dither_method::DitherMethod;

src/wand/macros.rs

@@ -258,7 +258,7 @@ macro_rules! mutations {
         $(
             $(#[$attr])*
             pub fn $fun(&self $(, $arg: $ty)*) -> Result<()> {
-                match unsafe { bindings::$c_fun(self.wand $(, $arg)*) } {
+                match unsafe { bindings::$c_fun(self.wand $(, $arg.into())*) } {
                     bindings::MagickBooleanType_MagickTrue => Ok(()),
                     _ => Err(MagickError(concat!(stringify!($c_fun), " invocation failed")))
                 }

src/wand/magick.rs

@@ -30,6 +30,7 @@ use crate::result::Result;
 
 use super::{DrawingWand, PixelWand};
 use crate::{
+    AlphaChannelOption,
     ColorspaceType,
     CompositeOperator,
     DitherMethod,
@@ -1142,8 +1143,7 @@ impl MagickWand {
         MagickBrightnessContrastImage => brightness_contrast_image(brightness: f64, contrast: f64)
 
         /// Set the image alpha channel mode.
-        MagickSetImageAlphaChannel => set_image_alpha_channel(
-            alpha_channel: bindings::AlphaChannelOption)
+        MagickSetImageAlphaChannel => set_image_alpha_channel(alpha_channel: AlphaChannelOption)
 
         /// Discard all but one of any pixel color.
         MagickUniqueImageColors => unique_image_colors()

tests/lib.rs

@@ -317,7 +317,7 @@ fn test_set_image_background_color() {
     let mut pw = PixelWand::new();
     pw.set_color("#0000FF").unwrap();
     wand.set_image_background_color(&pw).unwrap();
-    wand.set_image_alpha_channel(bindings::AlphaChannelOption_RemoveAlphaChannel)
+    wand.set_image_alpha_channel(magick_rust::AlphaChannelOption::Remove)
         .unwrap();
     let blob = wand.write_image_blob("rgb").unwrap();
     assert_eq!(0u8, blob[0]);