Add new BlackWhiteSmooth export option

ad-si · Jan 11, 2025 · 20e7734 · 20e7734
1 parent 7db1e97
commit 20e7734
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Showing 10 changed files with 90 additions and 13 deletions.
diff --git a/app/Main.hs b/app/Main.hs
@@ -4,7 +4,7 @@
 module Main where
 
 import Protolude (
-  Bool (True),
+  Bool (True, False),
   Char,
   Either (Left, Right),
   IO,
@@ -97,7 +97,7 @@ execWithArgs config cliArgs = do
           height = P.snd bitmapData.bitmapSize
         withForeignPtr (castForeignPtr bitmapData.bitmapPointer) $ \ptr -> do
           -- resutlImg <- grayscale width height ptr
-          resutlImg <- otsu_threshold_rgba width height ptr
+          resutlImg <- otsu_threshold_rgba width height False ptr
           resultImgForeignPtr <- newForeignPtr_ (castPtr resutlImg)
           let grayscalePicture =
                 bitmapOfForeignPtr

diff --git a/cbits/simplecv.c b/cbits/simplecv.c
@@ -217,6 +217,37 @@ void apply_global_threshold(
 }
 
 
+/**
+  * Applies two thresholds to the image data by blackening pixels
+  * below the lower threshold and whitening pixels above the upper threshold.
+  * Pixels between the two thresholds are scaled to the range [0, 255].
+  *
+  * @param img_length_px Length of the image data in pixels.
+  * @param data Pointer to the image data.
+  * @param lower_threshold Every pixel below this value will be blackened.
+  * @param upper_threshold Every pixel above this value will be whitened.
+  *
+  */
+void apply_double_threshold(
+  unsigned int img_length_px,
+  unsigned char *data,
+  unsigned char lower_threshold,
+  unsigned char upper_threshold
+) {
+  for (unsigned int i = 0; i < img_length_px; i++) {
+    if (data[i] < lower_threshold) {
+      data[i] = 0;
+    }
+    else if (data[i] > upper_threshold) {
+      data[i] = 255;
+    }
+    else {
+      data[i] = (data[i] - lower_threshold) * 255 / (upper_threshold - lower_threshold);
+    }
+  }
+}
+
+
 /**
   * Convert single channel grayscale image data to
   * RGBA row-major top-to-bottom image data.
@@ -254,12 +285,14 @@ unsigned char const * const single_to_multichannel(
   *
   * @param width Width of the image.
   * @param height Height of the image.
+  * @param use_double_threshold Use double thresholding.
   * @param data Pointer to the pixel data.
   * @return Pointer to the monochrome image data.
   */
 unsigned char const * const otsu_threshold_rgba(
   unsigned int width,
   unsigned int height,
+  bool use_double_threshold,
   unsigned char const * const data
 ) {
   unsigned char *grayscale_img = rgba_to_grayscale(width, height, data);
@@ -306,7 +339,23 @@ unsigned char const * const otsu_threshold_rgba(
     }
   }
 
-  apply_global_threshold(img_length_px, grayscale_img, optimal_threshold);
+  const int threshold_range_offset = 16;
+
+  if (use_double_threshold) {
+    apply_double_threshold(
+      img_length_px,
+      grayscale_img,
+      optimal_threshold - threshold_range_offset,
+      optimal_threshold + threshold_range_offset
+    );
+  }
+  else {
+    apply_global_threshold(
+      img_length_px,
+      grayscale_img,
+      optimal_threshold
+    );
+  }
 
   unsigned char const * const monochrome_data = single_to_multichannel(
     width,

diff --git a/cbits/simplecv.h b/cbits/simplecv.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <stdbool.h>
+
 unsigned char const * const grayscale(
   unsigned int width,
   unsigned int height,
@@ -21,5 +23,6 @@ void apply_global_threshold(
 unsigned char const * const otsu_threshold_rgba(
   unsigned int width,
   unsigned int height,
+  bool use_double_threshold,
   unsigned char const * const data
 );
diff --git a/cbits/test.c b/cbits/test.c
@@ -17,7 +17,7 @@ int test_otsu_threshold () {
     0,0,0,255, 2,2,2,255, 9,9,9,255, 8,8,8,255
   };
 
-  unsigned char const * const monochrome_data = otsu_threshold_rgba(width, height, data);
+  unsigned char const * const monochrome_data = otsu_threshold_rgba(width, height, false, data);
 
   unsigned char expected_data[64] = {
     0,0,0,255, 0,0,0,255, 255,255,255,255, 255,255,255,255,

diff --git a/images/words.afdesign b/images/words.afdesign
diff --git a/images/words.png b/images/words.png
diff --git a/source/Lib.hs b/source/Lib.hs
@@ -592,6 +592,8 @@ handleImageViewEvent event appState =
           submitSelection appState GrayscaleExport
         Just (Button{text = "Save BW"}) ->
           submitSelection appState BlackWhiteExport
+        Just (Button{text = "Save BW Smooth"}) ->
+          submitSelection appState BlackWhiteSmoothExport
         _ -> do
           let
             point = appCoordToImgCoord appState clickedPoint
@@ -709,6 +711,9 @@ getConvertArgs inPath outPath projMap shape exportMode =
       UnmodifiedExport -> []
       GrayscaleExport -> ["-colorspace", "gray", "-normalize"]
       BlackWhiteExport -> ["-auto-threshold", "OTSU", "-monochrome"]
+      -- TODO: Use the correct algorithm as seen in
+      --       https://github.com/ad-si/dotfiles/blob/master/bin/level
+      BlackWhiteSmoothExport -> ["-auto-threshold", "OTSU", "-monochrome"]
     <> [ "+repage"
        , fixOutputPath exportMode outPath
        ]
@@ -831,6 +836,7 @@ correctAndWrite transformBackend inPath outPath ((bl, _), (tl, _), (tr, _), (br,
         UnmodifiedExport -> writeImage outPath corrected
         GrayscaleExport -> pure ()
         BlackWhiteExport -> pure ()
+        BlackWhiteSmoothExport -> pure ()
     --
     SimpleCVBackend -> do
       P.putText "ℹ️ Use SimpleCV backend"
@@ -923,7 +929,13 @@ correctAndWrite transformBackend inPath outPath ((bl, _), (tl, _), (tr, _), (br,
                 savePngImage outPath (ImageRGBA8 grayImg)
               --
               BlackWhiteExport -> do
-                bwImgPtr <- SCV.otsu_threshold_rgba width height resutlImg
+                bwImgPtr <- SCV.otsu_threshold_rgba width height False resutlImg
+                bwImgForeignPtr <- newForeignPtr_ (castPtr bwImgPtr)
+                let bwImg = imageFromUnsafePtr width height bwImgForeignPtr
+                savePngImage outPath (ImageRGBA8 bwImg)
+              --
+              BlackWhiteSmoothExport -> do
+                bwImgPtr <- SCV.otsu_threshold_rgba width height True resutlImg
                 bwImgForeignPtr <- newForeignPtr_ (castPtr bwImgPtr)
                 let bwImg = imageFromUnsafePtr width height bwImgForeignPtr
                 savePngImage outPath (ImageRGBA8 bwImg)

diff --git a/source/SimpleCV.chs b/source/SimpleCV.chs
@@ -6,6 +6,7 @@ import Protolude (
   identity,
   Int,
   IO,
+  Bool,
   Ptr,
   Show,
   return,
@@ -110,6 +111,7 @@ instance Storable Matrix3x3 where
 {#fun otsu_threshold_rgba
   {               `Int'        -- ^ width
   ,               `Int'        -- ^ height
+  ,               `Bool'       -- ^ whether to use double thresholding
   , identity      `Ptr CUChar' -- ^ Original image data
   } -> `Ptr CUChar' castPtr    -- ^ Thresholded image data
 #}

diff --git a/source/Types.hs b/source/Types.hs
@@ -138,6 +138,7 @@ data ExportMode
   = UnmodifiedExport
   | GrayscaleExport
   | BlackWhiteExport
+  | BlackWhiteSmoothExport
 
 
 data UiComponent
@@ -196,7 +197,7 @@ data AppState = AppState
 appInitialWidth, appInitialHeight, sidebarInitialWidth :: Int
 appInitialWidth = 1280
 appInitialHeight = 960
-sidebarInitialWidth = 150
+sidebarInitialWidth = 180
 
 
 initialState :: AppState
@@ -218,19 +219,25 @@ initialState =
     , uiComponents =
         [ Button
             { text = "Save"
-            , width = 110
+            , width = 160
             , height = 30
             , bgColor = 0
             }
         , Button
             { text = "Save Gray"
-            , width = 110
+            , width = 160
             , height = 30
             , bgColor = 0
             }
         , Button
             { text = "Save BW"
-            , width = 110
+            , width = 160
+            , height = 30
+            , bgColor = 0
+            }
+        , Button
+            { text = "Save BW Smooth"
+            , width = 160
             , height = 30
             , bgColor = 0
             }

diff --git a/source/Utils.hs b/source/Utils.hs
@@ -83,19 +83,23 @@ getWordSprite spriteText =
     Bitmap bitmapData -> case spriteText of
       "Save" ->
         BitmapSection
-          Rectangle{rectPos = (0, 40), rectSize = (90, 20)}
+          Rectangle{rectPos = (-5, 40), rectSize = (150, 20)}
           bitmapData
       "Save BW" ->
         BitmapSection
-          Rectangle{rectPos = (0, 60), rectSize = (90, 20)}
+          Rectangle{rectPos = (-5, 60), rectSize = (150, 20)}
           bitmapData
       "Save Gray" ->
         BitmapSection
-          Rectangle{rectPos = (0, 80), rectSize = (90, 20)}
+          Rectangle{rectPos = (-5, 80), rectSize = (150, 20)}
           bitmapData
       "Select Files" ->
         BitmapSection
-          Rectangle{rectPos = (0, 140), rectSize = (100, 20)}
+          Rectangle{rectPos = (-5, 140), rectSize = (150, 20)}
+          bitmapData
+      "Save BW Smooth" ->
+        BitmapSection
+          Rectangle{rectPos = (-5, 160), rectSize = (150, 20)}
           bitmapData
       _ -> mempty
     _ -> mempty