New setting to control the quality of exported PDFs (#70)

imageprocessing/src/main/java/org/fairscan/imageprocessing/ColorDetection.kt

@@ -25,7 +25,6 @@ import org.opencv.core.Size
 import org.opencv.imgproc.Imgproc
 import org.opencv.imgproc.Imgproc.fillConvexPoly
 import kotlin.math.roundToInt
-import kotlin.math.sqrt
 
 fun isColoredDocument(
     img: Mat,
@@ -97,18 +96,6 @@ fun isColoredDocument(
     return proportion > proportionThreshold
 }
 
-private fun resizeForMaxPixels(img: Mat, maxPixels: Double): Mat {
-    val origPixels = img.width() * img.height()
-    if (origPixels <= maxPixels) {
-        return img.clone()
-    }
-    val scale = sqrt(maxPixels / origPixels)
-    val size = Size(img.width() * scale, img.height() * scale)
-    val resizedImg = Mat()
-    Imgproc.resize(img, resizedImg, size, 0.0, 0.0, Imgproc.INTER_AREA)
-    return resizedImg
-}
-
 private fun chroma(a: Mat, b: Mat): Mat {
     val aFloat = Mat()
     val bFloat = Mat()

imageprocessing/src/main/java/org/fairscan/imageprocessing/DocumentDetection.kt

@@ -32,15 +32,6 @@ interface Mask {
     fun toMat(): Mat
 }
 
-data class PageAnalysis(
-    val isColored: Boolean,
-)
-
-data class ExtractedDocument(
-    val image: Mat,
-    val pageAnalysis: PageAnalysis,
-)
-
 fun detectDocumentQuad(mask: Mask, isLiveAnalysis: Boolean, minQuadAreaRatio: Double = 0.02): Quad? {
     val mat = mask.toMat()
     val (biggest: MatOfPoint2f?, area) = biggestContour(mat)
@@ -125,8 +116,9 @@ fun extractDocument(
     inputMat: Mat,
     quad: Quad,
     rotationDegrees: Int,
-    mask: Mask,
-): ExtractedDocument {
+    isColored: Boolean,
+    maxPixels: Long,
+): Mat {
     val widthTop = norm(quad.topLeft, quad.topRight)
     val widthBottom = norm(quad.bottomLeft, quad.bottomRight)
     val targetWidth = (widthTop + widthBottom) / 2
@@ -153,27 +145,11 @@ fun extractDocument(
     val outputSize = Size(targetWidth, targetHeight)
     Imgproc.warpPerspective(inputMat, outputMat, transform, outputSize)
 
-    val resized = resize(outputMat, 1500.0)
-    val isColored = isColoredDocument(inputMat, mask, quad)
+    val resized = resizeForMaxPixels(outputMat, maxPixels.toDouble())
     val enhanced = enhanceCapturedImage(resized, isColored)
     val rotated = rotate(enhanced, rotationDegrees)
 
-    return ExtractedDocument(rotated, PageAnalysis(isColored))
-}
-
-fun resize(original: Mat, targetMax: Double): Mat {
-    val origSize = original.size()
-    if (max(origSize.width, origSize.height) < targetMax)
-        return original;
-    var targetWidth = targetMax
-    var targetHeight = origSize.height * targetWidth / origSize.width
-    if (origSize.width < origSize.height) {
-        targetHeight = targetMax
-        targetWidth = origSize.width * targetHeight / origSize.height
-    }
-    val result = Mat()
-    Imgproc.resize(original, result, Size(targetWidth, targetHeight), 0.0, 0.0, Imgproc.INTER_AREA)
-    return result
+    return rotated
 }
 
 fun rotate(input: Mat, degrees: Int): Mat {

imageprocessing/src/main/java/org/fairscan/imageprocessing/Utils.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2025 Pierre-Yves Nicolas
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.fairscan.imageprocessing
+
+import org.opencv.core.Mat
+import org.opencv.core.Size
+import org.opencv.imgproc.Imgproc
+import kotlin.math.sqrt
+
+fun resizeForMaxPixels(img: Mat, maxPixels: Double): Mat {
+    val origPixels = img.width() * img.height()
+    if (origPixels <= maxPixels) {
+        return img.clone()
+    }
+    val scale = sqrt(maxPixels / origPixels)
+    val size = Size(img.width() * scale, img.height() * scale)
+    val resizedImg = Mat()
+    Imgproc.resize(img, resizedImg, size, 0.0, 0.0, Imgproc.INTER_AREA)
+    return resizedImg
+}