From ec1a05800e9793d6efed8dca972e8943ff7a131a Mon Sep 17 00:00:00 2001
From: Onetchou <83351185+Onetchou@users.noreply.github.com>
Date: Sat, 23 Nov 2024 18:25:43 +0100
Subject: [PATCH] fix: bounding boxes of exported svg pattern pieces are now
 correct

---
 src/libs/vformat/svg_generator.cpp | 68 ++++++++++++++++++++++++++++--
 src/libs/vformat/svg_generator.h   |  4 ++
 2 files changed, 68 insertions(+), 4 deletions(-)

diff --git a/src/libs/vformat/svg_generator.cpp b/src/libs/vformat/svg_generator.cpp
index cd5efe4cf4f9..35da62719277 100644
--- a/src/libs/vformat/svg_generator.cpp
+++ b/src/libs/vformat/svg_generator.cpp
@@ -63,7 +63,7 @@ QDomDocument SvgGenerator::mergeSvgDoms()
         return QDomDocument();
     }
 
-    QDomDocument mergedSvg = m_domList.at(0);
+    QDomDocument mergedSvg = m_domList.at(0).cloneNode().toDocument();
 
     QDomElement mergedSvgRoot = mergedSvg.documentElement();
     if (mergedSvgRoot.tagName() != "svg") {
@@ -71,7 +71,14 @@ QDomDocument SvgGenerator::mergeSvgDoms()
         return QDomDocument();
     }
 
-    for (int i = 1; i < m_domList.size(); ++i) {
+    QDomNodeList mergedSvgGroups = mergedSvgRoot.elementsByTagName("g");
+    if (mergedSvgGroups.isEmpty()) {
+        qDebug() << "Error : the SVG does not contain a <g> tag.";
+        return QDomDocument();
+    }
+    mergedSvgRoot.removeChild(mergedSvgGroups.at(0));
+
+    for (int i = 0; i < m_domList.size(); ++i) {
         QDomDocument domSvg = m_domList.at(i);
         QDomElement svgRoot = domSvg.documentElement();
         if (svgRoot.tagName() != "svg") {
@@ -84,12 +91,67 @@ QDomDocument SvgGenerator::mergeSvgDoms()
             return QDomDocument();
         }
         QDomElement mainGroup = svgGroups.at(0).toElement();
+        cleanSvg(mainGroup);
         mergedSvgRoot.appendChild(mainGroup);
     }
 
     return mergedSvg;
 }
 
+//---------------------------------------------------------------------------------------------------------------------
+/**
+ * @brief Remove empty groups from the SVG
+ * @return void
+ * @details This function removes empty unuseful groups from the exported SVG.
+ *          Those empty groups were generated by Qt svg generator.
+ */
+void SvgGenerator::removeEmptyGroups(QDomElement &mainGroup)
+{
+    QDomNodeList groups = mainGroup.elementsByTagName("g");
+    for (int i = 0; i < groups.size(); ++i) {
+        QDomElement group = groups.at(i).toElement();
+        if (group.childNodes().isEmpty()) {
+            if (mainGroup.removeChild(group).isNull()) {
+                qDebug() << "Error : could not remove empty group";
+            }
+        }
+    }
+}
+
+//---------------------------------------------------------------------------------------------------------------------
+/**
+ * @brief Remove the M0,0 origin path from the SVG
+ * @return void
+ * @details This function removes tht M0,0 origin path from the SVG.
+ *          If this path is not removed, the bounding box of the exported pattern piece
+ *          when opened in a svg editing software can be wrong.
+ */
+void SvgGenerator::removeEmptyOriginPath(QDomElement &mainGroup)
+{
+    QDomNodeList paths = mainGroup.elementsByTagName("path");
+    for (int i = 0; i < paths.size(); ++i) {
+        QDomElement path = paths.at(i).toElement();
+        if (path.attribute("d") == "M0,0") {
+            QDomElement parentGroup = path.parentNode().toElement();
+            parentGroup.removeChild(path);
+            mainGroup.removeChild(parentGroup);
+            break;
+        }
+    }
+}
+
+
+//---------------------------------------------------------------------------------------------------------------------
+/**
+ * @brief Clean the SVG
+ * @return void
+ * @details This function cleans the SVG by removing empty groups and the origin M0,0 path
+ */
+void SvgGenerator::cleanSvg(QDomElement &mainGroup)
+{
+    removeEmptyGroups(mainGroup);
+    removeEmptyOriginPath(mainGroup);
+}
 
 //---------------------------------------------------------------------------------------------------------------------
 /**
@@ -101,8 +163,6 @@ QDomDocument SvgGenerator::mergeSvgDoms()
 */
 void SvgGenerator::addSvgFromScene(QGraphicsScene *scene)
 {
-
-
     QByteArray byteArray;
     QBuffer buffer(&byteArray);
     buffer.open(QIODevice::WriteOnly);
diff --git a/src/libs/vformat/svg_generator.h b/src/libs/vformat/svg_generator.h
index dffb446bb86b..32ed05e8a8ac 100644
--- a/src/libs/vformat/svg_generator.h
+++ b/src/libs/vformat/svg_generator.h
@@ -45,6 +45,10 @@ class SvgGenerator
 private:
     QDomDocument mergeSvgDoms();
 
+    void removeEmptyGroups(QDomElement &mainGroup);
+    void removeEmptyOriginPath(QDomElement &mainGroup);
+    void cleanSvg(QDomElement &mainGroup);
+
     QGraphicsRectItem *m_paper;
     QString m_filepath;
     QString m_description;