From f923b80a23450ec8735b09f31768e0157dc802cf Mon Sep 17 00:00:00 2001
From: Jarol Rodriguez <jarolrod@tutanota.com>
Date: Mon, 7 Jun 2021 03:16:53 -0400
Subject: [PATCH] qt: make GUIUtil::ThemedLabel UI form friendly

This makes the GUIUtil::ThemedLabel class able to be used in UI form
files. This is accomplished by introducing a form file friendly
constructor which only takes in a `QWidget* parent`.

You cannot pass in the `platform_style` when initializing a
GUIUtil::ThemedLabel in a UI form file. This introduces a
`setPlatformStyle` function to be able to pass in the `platform_style`
at a later point.

Additionally; because we are not initializing the class with a
`platform_style`, we need to implement a check in `updateThemedPixmap`
to only occur when the `m_platform_style` has been set. A segfault would
occur without this conditional as a `ChangeEvent` occurs on application
start
---
 src/qt/guiutil.cpp | 14 +++++++++++++-
 src/qt/guiutil.h   |  4 +++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/qt/guiutil.cpp b/src/qt/guiutil.cpp
index 393dca8ccd0..98bbe778148 100644
--- a/src/qt/guiutil.cpp
+++ b/src/qt/guiutil.cpp
@@ -793,6 +793,11 @@ qreal calculateIdealFontSize(int width, const QString& text, QFont font, qreal m
     return font_size;
 }
 
+ThemedLabel::ThemedLabel(QWidget* parent)
+{
+    QLabel{parent};
+}
+
 ThemedLabel::ThemedLabel(const PlatformStyle* platform_style, QWidget* parent)
     : QLabel{parent}, m_platform_style{platform_style}
 {
@@ -807,6 +812,11 @@ void ThemedLabel::setThemedPixmap(const QString& image_filename, int width, int
     updateThemedPixmap();
 }
 
+void ThemedLabel::setPlatformStyle(const PlatformStyle* platform_style)
+{
+    m_platform_style = platform_style;
+    assert(m_platform_style);
+}
 void ThemedLabel::changeEvent(QEvent* e)
 {
 #ifdef Q_OS_MACOS
@@ -819,7 +829,9 @@ void ThemedLabel::changeEvent(QEvent* e)
 
 void ThemedLabel::updateThemedPixmap()
 {
-    setPixmap(m_platform_style->SingleColorIcon(m_image_filename).pixmap(m_pixmap_width, m_pixmap_height));
+    if (m_platform_style) {
+        setPixmap(m_platform_style->SingleColorIcon(m_image_filename).pixmap(m_pixmap_width, m_pixmap_height));
+    }
 }
 
 ClickableLabel::ClickableLabel(const PlatformStyle* platform_style, QWidget* parent)
diff --git a/src/qt/guiutil.h b/src/qt/guiutil.h
index 06a3b636686..93a0a8cc111 100644
--- a/src/qt/guiutil.h
+++ b/src/qt/guiutil.h
@@ -237,14 +237,16 @@ namespace GUIUtil
         Q_OBJECT
 
     public:
+        explicit ThemedLabel(QWidget* parent = nullptr);
         explicit ThemedLabel(const PlatformStyle* platform_style, QWidget* parent = nullptr);
         void setThemedPixmap(const QString& image_filename, int width, int height);
+        void setPlatformStyle(const PlatformStyle* platform_style);
 
     protected:
         void changeEvent(QEvent* e) override;
 
     private:
-        const PlatformStyle* m_platform_style;
+        const PlatformStyle* m_platform_style = nullptr;
         QString m_image_filename;
         int m_pixmap_width;
         int m_pixmap_height;