aded FreeSize for cut marks, examples

cmd_examples/prep-help.bat

@@ -0,0 +1,2 @@
+..\pprep prep -h
+pause

cmd_examples_dev/prep-frame.bat

@@ -0,0 +1,11 @@
+..\target\release\pprep ^
+  --input ../test_data/*.png ^
+  --debug ^
+  prep ^
+    --output ../test_data/out/*-frame.png ^
+    --format 10cm/15cm ^
+	--padding 5mm/5mm/1cm/5mm ^
+	--margins 2mm ^
+	--cut-frame ./2mm ^
+	--dpi 300
+pause

cmd_examples_dev/prep-framed-size.bat

@@ -0,0 +1,11 @@
+..\target\release\pprep ^
+  --input ../test_data/*.png ^
+  --debug ^
+  prep ^
+    --output ../test_data/out/*-frame.png ^
+    --format 15cm/10cm ^
+    --framed-size 12cm/6cm ^
+	--padding 5mm/5mm/5mm/5mm ^
+	--cut-frame ./. ^
+	--dpi 300
+pause

cmd_examples_dev/prep-marks.bat

@@ -0,0 +1,11 @@
+..\target\release\pprep ^
+  --input ../test_data/*.png ^
+  --debug ^
+  prep ^
+    --output ../test_data/out/*-marks.png ^
+    --format 10cm/15cm ^
+	--padding 5mm/5mm/1cm/5mm ^
+	--margins 2mm ^
+	--cut-marks ./1mm ^
+	--dpi 300
+pause

src/op/prep.rs

@@ -3,7 +3,7 @@
 use crate::cli::parse;
 use crate::op::{ImageIoOperation, ImageOperation};
 use crate::units::color::Color;
-use crate::units::{format, LengthUnit, ScaleMode, Size};
+use crate::units::{format, FreeSize, LengthUnit, ScaleMode};
 use crate::units::{Borders, FixSize};
 use crate::util::ImageUtil;
 use image::imageops::FilterType;
@@ -37,11 +37,11 @@ pub struct PrepareImage {
 
     /// Cut marks with offset. Format <line-width>/<offset>. Use alternative to `--cut-frame`.
     #[structopt(name = "cut-marks", long)]
-    pub cut_marks: Option<Size>,
+    pub cut_marks: Option<FreeSize>,
 
     /// Cut frame. Format <line-width>/<extend>. Use alternative to `--cut-marks`.
     #[structopt(name = "cut-frame", long)]
-    pub cut_frame: Option<Size>,
+    pub cut_frame: Option<FreeSize>,
 
     /// Cut marks or frame color. Default: black.
     #[structopt(name = "cut-color", long)]
@@ -298,7 +298,7 @@ impl ImageIoOperation for PrepareImage {
         };
 
         // Calculates sizes, etc.
-        let (img, frame, padding, margins) =
+        let (img, _frame, padding, margins) =
             self.calc_sizes(width, height, image.width(), image.height(), rotate, dpi);
         let x_img = (margins.left().value() + padding.left().value()) as u32;
         let y_img = (margins.top().value() + padding.top().value()) as u32;

src/units/mod.rs

@@ -12,6 +12,7 @@ pub use length::LengthUnit;
 pub use length::ToLength;
 
 pub use size::FixSize;
+pub use size::FreeSize;
 pub use size::Size;
 
 pub use scale::Scale;

src/units/size.rs

@@ -122,6 +122,94 @@ impl fmt::Display for Size {
     }
 }
 
+#[derive(Debug, PartialEq, Clone)]
+pub struct FreeSize {
+    width: Option<Length>,
+    height: Option<Length>,
+}
+
+impl FreeSize {
+    pub fn new(width: Option<Length>, height: Option<Length>) -> Result<Self, ParseStructError> {
+        Ok(FreeSize { width, height })
+    }
+    /// Width of this size.
+    pub fn width(&self) -> &Option<Length> {
+        &self.width
+    }
+    /// Height of this size.
+    pub fn height(&self) -> &Option<Length> {
+        &self.height
+    }
+    /// Converts this size to pixels.
+    pub fn to_px(&self, dpi: f64) -> Size {
+        self.to(&LengthUnit::Px, dpi)
+    }
+    /// Converts this size to another unit.
+    pub fn to(&self, unit: &LengthUnit, dpi: f64) -> Size {
+        Size {
+            width: self.width.as_ref().and_then(|w| Some(w.to(unit, dpi))),
+            height: self.height.as_ref().and_then(|w| Some(w.to(unit, dpi))),
+        }
+    }
+    /// Rotates this size by 90° clockwise (i.e. swaps width and height).
+    pub fn rotate_90(&self) -> Size {
+        Size::new(self.height.clone(), self.width.clone()).unwrap()
+    }
+    /// Does this size require a dpi value for conversion to px?
+    pub fn needs_dpi(&self) -> bool {
+        let mut needs = false;
+        if let Some(w) = &self.width {
+            if w.needs_dpi() {
+                needs = true;
+            }
+        };
+        if let Some(h) = &self.height {
+            if h.needs_dpi() {
+                needs = true;
+            }
+        };
+        needs
+    }
+}
+
+impl FromStr for FreeSize {
+    type Err = Box<dyn Error>;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let parts: Vec<_> = s.split("/").collect();
+        if parts.len() != 2 {
+            return Err(Box::new(ParseStructError(format!(
+                "Unexpected size format in {}, expects `width/height`",
+                s
+            ))));
+        }
+        let width = if parts[0] == "." {
+            None
+        } else {
+            Some(parts[0].parse()?)
+        };
+        let height = if parts[1] == "." {
+            None
+        } else {
+            Some(parts[1].parse()?)
+        };
+        Ok(FreeSize { width, height })
+    }
+}
+impl fmt::Display for FreeSize {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let str1 = self
+            .width
+            .as_ref()
+            .map_or(".".to_string(), |l| l.to_string());
+        let str2 = self
+            .height
+            .as_ref()
+            .map_or(".".to_string(), |l| l.to_string());
+        write!(f, "{}/{}", str1, str2)
+    }
+}
+
 #[derive(Debug, PartialEq, Clone)]
 pub struct FixSize {
     width: Length,