Qt: new class ElidedLabel (#21277)

* shorten ssid

* truncate with ellipsis

* rename to trancate

* truncate 22 characters

* elidedLabel

* trimmed

* remove function elidedString

* cache elidedTest

* rebase master

* minimizeSizeHint

* add sizeHint

* cleanup

* revert

* inherit from QLabel

Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>
old-commit-hash: aee2b893a7

selfdrive/ui/qt/offroad/networking.cc

@@ -174,7 +174,7 @@ void WifiUI::refresh() {
   for (Network &network : wifi->seen_networks) {
     QHBoxLayout *hlayout = new QHBoxLayout;
 
-    QLabel *ssid_label = new QLabel(QString::fromUtf8(network.ssid));
+    ElidedLabel *ssid_label = new ElidedLabel(network.ssid);
     ssid_label->setStyleSheet("font-size: 55px;");
     hlayout->addWidget(ssid_label, 1, Qt::AlignLeft);
 

selfdrive/ui/qt/widgets/controls.cc

@@ -1,5 +1,8 @@
 #include "selfdrive/ui/qt/widgets/controls.h"
 
+#include <QPainter>
+#include <QStyleOption>
+
 QFrame *horizontal_line(QWidget *parent) {
   QFrame *line = new QFrame(parent);
   line->setFrameShape(QFrame::StyledPanel);
@@ -83,3 +86,31 @@ ButtonControl::ButtonControl(const QString &title, const QString &text, const QS
   QObject::connect(&btn, &QPushButton::released, this, &ButtonControl::released);
   hlayout->addWidget(&btn);
 }
+
+// ElidedLabel
+
+ElidedLabel::ElidedLabel(QWidget *parent) : ElidedLabel({}, parent) {}
+
+ElidedLabel::ElidedLabel(const QString &text, QWidget *parent) : QLabel(text.trimmed(), parent) {
+  setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
+  setMinimumWidth(1);
+}
+
+void ElidedLabel::resizeEvent(QResizeEvent* event) {
+  QLabel::resizeEvent(event);
+  lastText_ = elidedText_ = "";
+}
+
+void ElidedLabel::paintEvent(QPaintEvent *event) {
+  const QString curText = text();
+  if (curText != lastText_) {
+    elidedText_ = fontMetrics().elidedText(curText, Qt::ElideRight, contentsRect().width());
+    lastText_ = curText;
+  }
+
+  QPainter painter(this);
+  drawFrame(&painter);
+  QStyleOption opt;
+  opt.initFrom(this);
+  style()->drawItemText(&painter, contentsRect(), alignment(), opt.palette, isEnabled(), elidedText_, foregroundRole());
+}

selfdrive/ui/qt/widgets/controls.h

@@ -9,6 +9,20 @@
 #include "selfdrive/ui/qt/widgets/toggle.h"
 
 QFrame *horizontal_line(QWidget *parent = nullptr);
+
+class ElidedLabel : public QLabel {
+  Q_OBJECT
+
+ public:
+  explicit ElidedLabel(QWidget *parent = 0);
+  explicit ElidedLabel(const QString &text, QWidget *parent = 0);
+
+ protected:
+  void paintEvent(QPaintEvent *event) override;
+  void resizeEvent(QResizeEvent* event) override;
+  QString lastText_, elidedText_;
+};
+
 class AbstractControl : public QFrame {
   Q_OBJECT
 
@@ -48,7 +62,7 @@ public:
   void setText(const QString &text) { label.setText(text); }
 
 private:
-  QLabel label;
+  ElidedLabel label;
 };
 
 // widget for a button with a label