Fix selection rendering (#4830)

The rendering of selections was not aligned to the actual selection that took place for newlines at the end of messages, if they were the only part that was selected of that message.

In addition to that fix, we've already refactored the MessageLayoutContainer to try to make it a little bit more sane to work with in the future.

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

CHANGELOG.md

@@ -13,7 +13,7 @@
 - Bugfix: Fixed selection of tabs after closing a tab when using "Live Tabs Only". (#4770)
 - Bugfix: Fixed input in reply thread popup losing focus when dragging. (#4815)
 - Bugfix: Fixed the Quick Switcher (CTRL+K) from sometimes showing up on the wrong window. (#4819)
-- Bugfix: Fixed too much text being copied when copying chat messages. (#4812)
+- Bugfix: Fixed too much text being copied when copying chat messages. (#4812, #4830)
 - Dev: Fixed UTF16 encoding of `modes` file for the installer. (#4791)
 - Dev: Temporarily disable High DPI scaling on Qt6 builds on Windows. (#4767)
 - Dev: Tests now run on Ubuntu 22.04 instead of 20.04 to loosen C++ restrictions in tests. (#4774)

src/messages/Selection.hpp

@@ -1,18 +1,19 @@
 #pragma once
 
+#include <cstddef>
 #include <cstdint>
 #include <tuple>
 #include <utility>
 
 namespace chatterino {
 
 struct SelectionItem {
-    uint32_t messageIndex{0};
-    uint32_t charIndex{0};
+    size_t messageIndex{0};
+    size_t charIndex{0};
 
     SelectionItem() = default;
 
-    SelectionItem(uint32_t _messageIndex, uint32_t _charIndex)
+    SelectionItem(size_t _messageIndex, size_t _charIndex)
         : messageIndex(_messageIndex)
         , charIndex(_charIndex)
     {
@@ -73,7 +74,7 @@ struct Selection {
     }
 
     // Shift all message selection indices `offset` back
-    void shiftMessageIndex(uint32_t offset)
+    void shiftMessageIndex(size_t offset)
     {
         if (offset > this->selectionMin.messageIndex)
         {

src/messages/layouts/MessageLayout.cpp

@@ -143,7 +143,7 @@ void MessageLayout::actuallyLayout(int width, MessageElementFlags flags)
     bool hideSimilar = getSettings()->hideSimilar;
     bool hideReplies = !flags.has(MessageElementFlag::RepliedMessage);
 
-    this->container_.begin(width, this->scale_, messageFlags);
+    this->container_.beginLayout(width, this->scale_, messageFlags);
 
     for (const auto &element : this->message_->elements)
     {
@@ -184,7 +184,7 @@ void MessageLayout::actuallyLayout(int width, MessageElementFlags flags)
         this->deleteBuffer();
     }
 
-    this->container_.end();
+    this->container_.endLayout();
     this->height_ = this->container_.getHeight();
 
     // collapsed state
@@ -424,17 +424,17 @@ const MessageLayoutElement *MessageLayout::getElementAt(QPoint point)
     return this->container_.getElementAt(point);
 }
 
-int MessageLayout::getLastCharacterIndex() const
+size_t MessageLayout::getLastCharacterIndex() const
 {
     return this->container_.getLastCharacterIndex();
 }
 
-int MessageLayout::getFirstMessageCharacterIndex() const
+size_t MessageLayout::getFirstMessageCharacterIndex() const
 {
     return this->container_.getFirstMessageCharacterIndex();
 }
 
-int MessageLayout::getSelectionIndex(QPoint position)
+size_t MessageLayout::getSelectionIndex(QPoint position) const
 {
     return this->container_.getSelectionIndex(position);
 }

src/messages/layouts/MessageLayout.hpp

@@ -62,9 +62,23 @@ class MessageLayout
 
     // Elements
     const MessageLayoutElement *getElementAt(QPoint point);
-    int getLastCharacterIndex() const;
-    int getFirstMessageCharacterIndex() const;
-    int getSelectionIndex(QPoint position);
+
+    /**
+     * Get the index of the last character in this message's container
+     * This is the sum of all the characters in `elements_`
+     */
+    size_t getLastCharacterIndex() const;
+
+    /**
+     * Get the index of the first visible character in this message's container
+     * This is not always 0 in case there elements that are skipped
+     */
+    size_t getFirstMessageCharacterIndex() const;
+
+    /**
+     * Get the character index at the given position, in the context of selections
+     */
+    size_t getSelectionIndex(QPoint position) const;
     void addSelectionText(QString &str, uint32_t from = 0,
                           uint32_t to = UINT32_MAX,
                           CopyMode copymode = CopyMode::Everything);