From 065ee3565634186dc5579a5068a836ea25921a62 Mon Sep 17 00:00:00 2001
From: Yu-Ren Zhang <e8035669@gmail.com>
Date: Mon, 7 Nov 2022 16:12:24 +0800
Subject: [PATCH] Ensure resized image has the same format with the input
 image. Add `drawObjectLabels()` to draw all the labels

Signed-off-by: Yu-Ren Zhang <e8035669@gmail.com>
---
 label_img.cpp | 48 ++++++++++++++++++++++++++++++++++++++++--------
 label_img.h   |  1 +
 2 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/label_img.cpp b/label_img.cpp
index 119178d..1c1f41e 100644
--- a/label_img.cpp
+++ b/label_img.cpp
@@ -125,7 +125,8 @@ void label_img::openImage(const QString &qstrImg, bool &ret)
 
         m_inputImg          = img.copy();
         m_inputImg          = m_inputImg.convertToFormat(QImage::Format_RGB888);
-        m_resized_inputImg  = m_inputImg.scaled(this->width(), this->height(),Qt::IgnoreAspectRatio,Qt::SmoothTransformation);
+        m_resized_inputImg  = m_inputImg.scaled(this->width(), this->height(),Qt::IgnoreAspectRatio,Qt::SmoothTransformation)
+                .convertToFormat(QImage::Format_RGB888);
 
         m_bLabelingStarted  = false;
 
@@ -148,7 +149,8 @@ void label_img::showImage()
     if(m_inputImg.isNull()) return;
     if(m_resized_inputImg.width() != this->width() or m_resized_inputImg.height() != this->height())
     {
-        m_resized_inputImg = m_inputImg.scaled(this->width(), this->height(),Qt::IgnoreAspectRatio,Qt::SmoothTransformation);
+        m_resized_inputImg = m_inputImg.scaled(this->width(), this->height(),Qt::IgnoreAspectRatio,Qt::SmoothTransformation)
+                .convertToFormat(QImage::Format_RGB888);
     }
 
     QImage img = m_resized_inputImg;
@@ -156,6 +158,11 @@ void label_img::showImage()
     gammaTransform(img);
 
     QPainter painter(&img);
+    QFont font = painter.font();
+    int fontSize = 14, xMargin = 5, yMargin = 2;
+    font.setPixelSize(fontSize);
+    font.setBold(true);
+    painter.setFont(font);
 
     int penThick = 3;
 
@@ -164,6 +171,7 @@ void label_img::showImage()
     drawCrossLine(painter, crossLineColor, penThick);
     drawFocusedObjectBox(painter, Qt::magenta, penThick);
     drawObjectBoxes(painter, penThick);
+    drawObjectLabels(painter, penThick, fontSize, xMargin, yMargin);
 
     this->setPixmap(QPixmap::fromImage(img));
 }
@@ -269,19 +277,43 @@ void label_img::drawObjectBoxes(QPainter& painter, int thickWidth)
 {
     QPen pen;
     pen.setWidth(thickWidth);
-    QFont font = painter.font();
-    font.setPixelSize(12);
-    font.setBold(true);
-    painter.setFont(font);
 
     for(ObjectLabelingBox boundingbox: m_objBoundingBoxes)
     {
         pen.setColor(m_drawObjectBoxColor.at(boundingbox.label));
         painter.setPen(pen);
 
+        painter.drawRect(cvtRelativeToAbsoluteRectInUi(boundingbox.box));
+    }
+}
+
+void label_img::drawObjectLabels(QPainter& painter, int thickWidth, int fontPixelSize, int xMargin, int yMargin)
+{
+    QFontMetrics fontMetrics = painter.fontMetrics();
+    QPen blackPen;
+
+    for(ObjectLabelingBox boundingbox: m_objBoundingBoxes)
+    {
+        QColor labelColor = m_drawObjectBoxColor.at(boundingbox.label);
         QRect rectUi = cvtRelativeToAbsoluteRectInUi(boundingbox.box);
-        painter.drawRect(rectUi);
-        painter.drawText(rectUi.topLeft() + QPoint(5, 14 + 14 * boundingbox.label), m_objList.at(boundingbox.label));
+
+        QRect labelRect = fontMetrics.boundingRect(m_objList.at(boundingbox.label));
+        if (rectUi.top() > fontPixelSize + yMargin * 2 + thickWidth + 1) {
+            labelRect.moveTo(rectUi.topLeft() + QPoint(-thickWidth / 2, -(fontPixelSize + yMargin * 2 + thickWidth + 1)));
+            labelRect.adjust(0, 0, xMargin * 2, yMargin * 2);
+        } else {
+            labelRect.moveTo(rectUi.topLeft() + QPoint(-thickWidth / 2, 0));
+            labelRect.adjust(0, 0, xMargin * 2, yMargin * 2);
+        }
+        painter.fillRect(labelRect, labelColor);
+
+        if (qGray(m_drawObjectBoxColor.at(boundingbox.label).rgb()) > 120) {
+            blackPen.setColor(QColorConstants::Black);
+        } else {
+            blackPen.setColor(QColorConstants::White);
+        }
+        painter.setPen(blackPen);
+        painter.drawText(labelRect.topLeft() + QPoint(xMargin, yMargin + fontPixelSize), m_objList.at(boundingbox.label));
     }
 }
 
diff --git a/label_img.h b/label_img.h
index b862217..0a628a9 100644
--- a/label_img.h
+++ b/label_img.h
@@ -87,6 +87,7 @@ private:
     void drawCrossLine(QPainter& , QColor , int thickWidth = 3);
     void drawFocusedObjectBox(QPainter& , Qt::GlobalColor , int thickWidth = 3);
     void drawObjectBoxes(QPainter& , int thickWidth = 3);
+    void drawObjectLabels(QPainter& , int thickWidth = 3, int fontPixelSize = 14, int xMargin = 5, int yMargin = 2);
     void gammaTransform(QImage& image);
     void removeFocusedObjectBox(QPointF);
 };