feat(fix-orientation): manual per-image trim before page split

Add optional inward margins (source pixels) per image in Fix Orientation,
persisted in project XML, applied as pre-crop after rotation. Page Split
intersects its outline with any existing pre-crop. Panel: enable, margins,
reset.

Refs #129

Author: pablogventura

src/core/ImageTransformation.cpp

@@ -3,6 +3,8 @@
 
 #include "ImageTransformation.h"
 
+#include <QPolygonF>
+
 #include <cmath>
 
 #ifndef M_PI
@@ -192,6 +194,11 @@ void ImageTransformation::resetPostScale() {
   m_postScaleXform.reset();
 }
 
+QPolygonF ImageTransformation::origRectToPreCropSpace(const QRectF& rect) const {
+  const QTransform preScaleThenPreRotate(m_preScaleXform * m_preRotateXform);
+  return preScaleThenPreRotate.map(QPolygonF(rect));
+}
+
 void ImageTransformation::update() {
   const QTransform preScaleThenPreRotate(m_preScaleXform * m_preRotateXform);         // 12
   const QTransform preCropThenPostRotate(m_preCropXform * m_postRotateXform);         // 34

src/core/ImageTransformation.h

@@ -204,6 +204,12 @@ class ImageTransformation {
    */
   const QRectF& resultingRect() const { return m_resultingRect; }
 
+  /**
+   * \brief Map a rectangle from original image coordinates to the coordinate
+   *        system used by setPreCropArea() (after pre-scale and pre-rotate).
+   */
+  QPolygonF origRectToPreCropSpace(const QRectF& rect) const;
+
  private:
   QTransform calcCropXform(const QPolygonF& cropArea);
 

src/core/filters/fix_orientation/CMakeLists.txt

@@ -5,6 +5,7 @@ set(ui_files
     OptionsWidget.ui)
 
 set(sources
+    ImageTrim.cpp ImageTrim.h
     ImageView.cpp ImageView.h
     Filter.cpp Filter.h
     OptionsWidget.cpp OptionsWidget.h

src/core/filters/fix_orientation/CacheDrivenTask.cpp

@@ -6,6 +6,7 @@
 #include <utility>
 
 #include "ImageTransformation.h"
+#include "ImageTrim.h"
 #include "PageInfo.h"
 #include "Settings.h"
 #include "ThumbnailBase.h"
@@ -26,6 +27,12 @@ void CacheDrivenTask::process(const PageInfo& pageInfo, AbstractFilterDataCollec
   ImageTransformation xform(initialRect, pageInfo.metadata().dpi());
   xform.setPreRotation(m_settings->getRotationFor(pageInfo.imageId()));
 
+  const ImageTrim trim(m_settings->getTrim(pageInfo.imageId()));
+  if (trim.enabled) {
+    const QRect inner(trim.toInnerRect(pageInfo.metadata().size()));
+    xform.setPreCropArea(xform.origRectToPreCropSpace(QRectF(inner)));
+  }
+
   if (auto* col = dynamic_cast<PageOrientationCollector*>(collector)) {
     col->process(xform.preRotation());
   }

src/core/filters/fix_orientation/Filter.cpp

@@ -16,9 +16,9 @@
 #include "ProjectReader.h"
 #include "ProjectWriter.h"
 #include "Settings.h"
+#include "ImageTrim.h"
 #include "Task.h"
 #include "Utils.h"
-#include "XmlMarshaller.h"
 
 namespace fix_orientation {
 Filter::Filter(const PageSelectionAccessor& pageSelectionAccessor)
@@ -44,7 +44,7 @@ void Filter::performRelinking(const AbstractRelinker& relinker) {
 void Filter::preUpdateUI(FilterUiInterface* ui, const PageInfo& pageInfo) {
   if (m_optionsWidget.get()) {
     const OrthogonalRotation rotation(m_settings->getRotationFor(pageInfo.id().imageId()));
-    m_optionsWidget->preUpdateUI(pageInfo.id(), rotation);
+    m_optionsWidget->preUpdateUI(pageInfo, rotation);
     ui->setOptionsWidget(m_optionsWidget.get(), ui->KEEP_OWNERSHIP);
   }
 }
@@ -85,9 +85,22 @@ void Filter::loadSettings(const ProjectReader& reader, const QDomElement& filter
       continue;
     }
 
-    const OrthogonalRotation rotation(el.namedItem("rotation").toElement());
+    const QDomElement rotationEl(el.namedItem("rotation").toElement());
+    if (!rotationEl.isNull()) {
+      const OrthogonalRotation rotation(rotationEl);
+      m_settings->applyRotation(imageId, rotation);
+    }
 
-    m_settings->applyRotation(imageId, rotation);
+    const QDomElement trimEl(el.namedItem("trim").toElement());
+    if (!trimEl.isNull()) {
+      ImageTrim trim;
+      trim.enabled = (trimEl.attribute("enabled", "0") != "0");
+      trim.left = trimEl.attribute("left", "0").toInt();
+      trim.right = trimEl.attribute("right", "0").toInt();
+      trim.top = trimEl.attribute("top", "0").toInt();
+      trim.bottom = trimEl.attribute("bottom", "0").toInt();
+      m_settings->setTrim(imageId, trim);
+    }
   }
 
   loadImageSettings(reader, filterEl.namedItem("image-settings").toElement());
@@ -106,15 +119,26 @@ std::shared_ptr<CacheDrivenTask> Filter::createCacheDrivenTask(std::shared_ptr<p
 
 void Filter::writeParams(QDomDocument& doc, QDomElement& filterEl, const ImageId& imageId, int numericId) const {
   const OrthogonalRotation rotation(m_settings->getRotationFor(imageId));
-  if (rotation.toDegrees() == 0) {
+  const ImageTrim trim(m_settings->getTrim(imageId));
+
+  if ((rotation.toDegrees() == 0) && !trim.enabled) {
     return;
   }
 
-  XmlMarshaller marshaller(doc);
-
   QDomElement imageEl(doc.createElement("image"));
   imageEl.setAttribute("id", numericId);
-  imageEl.appendChild(rotation.toXml(doc, "rotation"));
+  if (rotation.toDegrees() != 0) {
+    imageEl.appendChild(rotation.toXml(doc, "rotation"));
+  }
+  if (trim.enabled) {
+    QDomElement trimEl(doc.createElement("trim"));
+    trimEl.setAttribute("enabled", "1");
+    trimEl.setAttribute("left", QString::number(trim.left));
+    trimEl.setAttribute("right", QString::number(trim.right));
+    trimEl.setAttribute("top", QString::number(trim.top));
+    trimEl.setAttribute("bottom", QString::number(trim.bottom));
+    imageEl.appendChild(trimEl);
+  }
   filterEl.appendChild(imageEl);
 }
 

src/core/filters/fix_orientation/ImageTrim.cpp

@@ -0,0 +1,41 @@
+// Copyright (C) 2019  Joseph Artsimovich <joseph.artsimovich@gmail.com>, 4lex4 <4lex49@zoho.com>
+// Use of this source code is governed by the GNU GPLv3 license that can be found in the LICENSE file.
+
+#include "ImageTrim.h"
+
+#include <algorithm>
+
+namespace fix_orientation {
+
+namespace {
+
+const int kMinInnerSide = 32;
+
+}  // namespace
+
+QRect ImageTrim::toInnerRect(const QSize& imageSize) const {
+  if (!enabled || imageSize.width() <= 0 || imageSize.height() <= 0) {
+    return QRect(0, 0, imageSize.width(), imageSize.height());
+  }
+
+  int l = std::max(0, left);
+  int t = std::max(0, top);
+  int r = std::max(0, right);
+  int b = std::max(0, bottom);
+
+  int w = imageSize.width() - l - r;
+  int h = imageSize.height() - t - b;
+  w = std::max(kMinInnerSide, w);
+  h = std::max(kMinInnerSide, h);
+
+  if (l + w > imageSize.width()) {
+    l = std::max(0, imageSize.width() - w);
+  }
+  if (t + h > imageSize.height()) {
+    t = std::max(0, imageSize.height() - h);
+  }
+
+  return QRect(l, t, w, h);
+}
+
+}  // namespace fix_orientation

src/core/filters/fix_orientation/ImageTrim.h

@@ -0,0 +1,27 @@
+// Copyright (C) 2019  Joseph Artsimovich <joseph.artsimovich@gmail.com>, 4lex4 <4lex49@zoho.com>
+// Use of this source code is governed by the GNU GPLv3 license that can be found in the LICENSE file.
+
+#ifndef SCANTAILOR_FIX_ORIENTATION_IMAGETRIM_H_
+#define SCANTAILOR_FIX_ORIENTATION_IMAGETRIM_H_
+
+#include <QRect>
+
+namespace fix_orientation {
+
+/**
+ * Inward crop from each edge of the source image, in integer source pixels.
+ * When disabled, other fields are ignored.
+ */
+struct ImageTrim {
+  bool enabled = false;
+  int left = 0;
+  int top = 0;
+  int right = 0;
+  int bottom = 0;
+
+  QRect toInnerRect(const QSize& imageSize) const;
+};
+
+}  // namespace fix_orientation
+
+#endif

src/core/filters/fix_orientation/OptionsWidget.cpp

@@ -5,6 +5,9 @@
 
 #include <core/IconProvider.h>
 
+#include <QSize>
+
+#include <algorithm>
 #include <cassert>
 #include <utility>
 
@@ -14,6 +17,12 @@
 #include "Settings.h"
 
 namespace fix_orientation {
+namespace {
+
+const int kMinInnerSide = 32;
+
+}  // namespace
+
 OptionsWidget::OptionsWidget(std::shared_ptr<Settings> settings, const PageSelectionAccessor& pageSelectionAccessor)
     : m_settings(std::move(settings)),
       m_pageSelectionAccessor(pageSelectionAccessor),
@@ -26,12 +35,15 @@ OptionsWidget::OptionsWidget(std::shared_ptr<Settings> settings, const PageSelec
 
 OptionsWidget::~OptionsWidget() = default;
 
-void OptionsWidget::preUpdateUI(const PageId& pageId, const OrthogonalRotation rotation) {
+void OptionsWidget::preUpdateUI(const PageInfo& pageInfo, const OrthogonalRotation rotation) {
   auto block = m_connectionManager.getScopedBlock();
 
-  m_pageId = pageId;
+  m_pageId = pageInfo.id();
+  m_imagePixelSize = pageInfo.metadata().size();
   m_rotation = rotation;
   setRotationPixmap();
+  updateTrimMaximums();
+  pullTrimToControls();
 }
 
 void OptionsWidget::postUpdateUI(const OrthogonalRotation rotation) {
@@ -100,6 +112,76 @@ void OptionsWidget::setRotation(const OrthogonalRotation& rotation) {
   emit invalidateThumbnail(m_pageId);
 }
 
+void OptionsWidget::trimEnableToggled(const bool checked) {
+  trimLeftSpin->setEnabled(checked);
+  trimRightSpin->setEnabled(checked);
+  trimTopSpin->setEnabled(checked);
+  trimBottomSpin->setEnabled(checked);
+  resetTrimBtn->setEnabled(checked);
+  if (!checked) {
+    m_settings->clearTrim(m_pageId.imageId());
+    emit invalidateThumbnail(m_pageId);
+    return;
+  }
+  pushTrimFromControls();
+}
+
+void OptionsWidget::trimMarginsChanged(const int) {
+  if (!trimEnabledCheck->isChecked()) {
+    return;
+  }
+  pushTrimFromControls();
+}
+
+void OptionsWidget::resetTrim() {
+  auto block = m_connectionManager.getScopedBlock();
+  trimLeftSpin->setValue(0);
+  trimRightSpin->setValue(0);
+  trimTopSpin->setValue(0);
+  trimBottomSpin->setValue(0);
+  if (trimEnabledCheck->isChecked()) {
+    pushTrimFromControls();
+  } else {
+    m_settings->clearTrim(m_pageId.imageId());
+    emit invalidateThumbnail(m_pageId);
+  }
+}
+
+void OptionsWidget::updateTrimMaximums() {
+  const int w = m_imagePixelSize.width();
+  const int h = m_imagePixelSize.height();
+  const int maxSide = std::max(0, std::max(w, h) - kMinInnerSide);
+  trimLeftSpin->setMaximum(maxSide);
+  trimRightSpin->setMaximum(maxSide);
+  trimTopSpin->setMaximum(maxSide);
+  trimBottomSpin->setMaximum(maxSide);
+}
+
+void OptionsWidget::pullTrimToControls() {
+  const ImageTrim trim(m_settings->getTrim(m_pageId.imageId()));
+  trimEnabledCheck->setChecked(trim.enabled);
+  trimLeftSpin->setValue(trim.left);
+  trimRightSpin->setValue(trim.right);
+  trimTopSpin->setValue(trim.top);
+  trimBottomSpin->setValue(trim.bottom);
+  trimLeftSpin->setEnabled(trim.enabled);
+  trimRightSpin->setEnabled(trim.enabled);
+  trimTopSpin->setEnabled(trim.enabled);
+  trimBottomSpin->setEnabled(trim.enabled);
+  resetTrimBtn->setEnabled(trim.enabled);
+}
+
+void OptionsWidget::pushTrimFromControls() {
+  ImageTrim trim;
+  trim.enabled = true;
+  trim.left = trimLeftSpin->value();
+  trim.right = trimRightSpin->value();
+  trim.top = trimTopSpin->value();
+  trim.bottom = trimBottomSpin->value();
+  m_settings->setTrim(m_pageId.imageId(), trim);
+  emit invalidateThumbnail(m_pageId);
+}
+
 void OptionsWidget::setRotationPixmap() {
   QIcon icon;
   switch (m_rotation.toDegrees()) {
@@ -128,6 +210,12 @@ void OptionsWidget::setupUiConnections() {
   CONNECT(rotateRightBtn, SIGNAL(clicked()), this, SLOT(rotateRight()));
   CONNECT(resetBtn, SIGNAL(clicked()), this, SLOT(resetRotation()));
   CONNECT(applyToBtn, SIGNAL(clicked()), this, SLOT(showApplyToDialog()));
+  CONNECT(trimEnabledCheck, SIGNAL(toggled(bool)), this, SLOT(trimEnableToggled(bool)));
+  CONNECT(trimLeftSpin, SIGNAL(valueChanged(int)), this, SLOT(trimMarginsChanged(int)));
+  CONNECT(trimRightSpin, SIGNAL(valueChanged(int)), this, SLOT(trimMarginsChanged(int)));
+  CONNECT(trimTopSpin, SIGNAL(valueChanged(int)), this, SLOT(trimMarginsChanged(int)));
+  CONNECT(trimBottomSpin, SIGNAL(valueChanged(int)), this, SLOT(trimMarginsChanged(int)));
+  CONNECT(resetTrimBtn, SIGNAL(clicked()), this, SLOT(resetTrim()));
 }
 
 #undef CONNECT
@@ -137,4 +225,4 @@ void OptionsWidget::setupIcons() {
   rotateLeftBtn->setIcon(iconProvider.getIcon("object-rotate-left"));
   rotateRightBtn->setIcon(iconProvider.getIcon("object-rotate-right"));
 }
-}  // namespace fix_orientation
+}  // namespace fix_orientation