more setup for moving to multiple preview images

src/file_data.rs

@@ -1,7 +1,6 @@
-use factor::factor::factor;
-
 use crate::image::Image;
 use crate::parser::ParserType;
+use crate::ImageType;
 
 pub struct Raw(Vec<u8>);
 
@@ -12,23 +11,17 @@ impl Raw {
     fn byte_count(&self) -> usize {
         self.0.len()
     }
-    fn cga_count(&self) -> usize {
-        self.byte_count() * 4
-    }
-    fn ega_count(&self) -> usize {
-        self.byte_count() * 2
-    }
-    pub fn cga_possible(&self) -> bool {
-        self.cga_count() <= 64_000
-    }
-    pub fn cga_fullscreen(&self) -> bool {
-        self.cga_count() == 64_000
+
+    pub fn pixel_count(&self, itype: ImageType) -> usize {
+        itype.pixel_count(self.byte_count())
     }
-    pub fn cga_widths(&self) -> Vec<i64> {
-        factor(self.cga_count().try_into().unwrap())
+
+    pub fn fullscreen(&self, itype: ImageType) -> bool {
+        itype.fullscreen(self.byte_count())
     }
-    pub fn ega_widths(&self) -> Vec<i64> {
-        factor(self.ega_count().try_into().unwrap())
+
+    pub fn widths(&self, itype: ImageType) -> Vec<i64> {
+        itype.widths(self.byte_count())
     }
 
     pub fn parse(&self, parser: ParserType, width: usize) -> Image {

src/lib.rs

@@ -1,5 +1,7 @@
 #![doc = include_str!("../README.md")]
 
+use factor::factor::factor;
+
 pub mod color;
 pub mod file_data;
 pub mod image;
@@ -38,10 +40,31 @@ impl ImageType {
             Self::EGA => 16,
         }
     }
+
     pub fn word_size(&self) -> usize {
         match self {
             Self::CGA => 2,
             Self::EGA => 4,
         }
     }
+
+    pub fn words_per_byte(&self) -> usize {
+        8 / self.word_size()
+    }
+
+    pub fn pixel_count(&self, byte_count: usize) -> usize {
+        byte_count * self.words_per_byte()
+    }
+
+    pub fn fullscreen(&self, byte_count: usize) -> bool {
+        //this does not yet handle all the different EGA cases, or cga monochrome etc
+        self.pixel_count(byte_count) == 64_000
+    }
+
+    pub fn widths(&self, byte_count: usize) -> Vec<i64> {
+        factor(self.pixel_count(byte_count).try_into().unwrap())
+            .into_iter()
+            .filter(|&x| x < 80)
+            .collect()
+    }
 }