Implementing a Text-Heavy UI
What's the best approach for implementing a text-heavy UI, like a chat system?
Implementing a text-heavy UI, such as a chat system, requires careful consideration of performance and usability. Here's an approach you can take:
Efficient Text Rendering
Use the WrappedText class we created earlier, but extend it to handle multiple messages:
#include <SDL.h>
#include <SDL_ttf.h>
#include <deque>
#include <string>
#include <vector>
class ChatSystem : public WrappedText {
public:
ChatSystem(int FontSize, int MaxWidth,
int MaxMessages)
: WrappedText{"", FontSize, MaxWidth},
MaxMessages{MaxMessages} {}
void AddMessage(const std::string& Message) {
Messages.push_front(Message);
if (Messages.size() > MaxMessages) {
Messages.pop_back();
}
UpdateSurface();
}
private:
void UpdateSurface() {
std::string CombinedText;
for (const auto& Msg : Messages) {
CombinedText += Msg + "\n";
}
CreateSurface(CombinedText);
}
std::deque<std::string> Messages;
int MaxMessages;
};Memory Management
To prevent excessive memory usage, limit the number of messages stored and rendered:
int main() {
SDL_Init(SDL_INIT_VIDEO);
TTF_Init();
// Font size 18, 400px wide, max 50 messages
// Add some messages
ChatSystem Chat{18, 400, 50};
Chat.AddMessage("Hello, world!");
Chat.
AddMessage("Welcome to the chat system.");
// Your SDL rendering loop here...
TTF_Quit();
SDL_Quit();
return 0;
}Scrolling
For scrolling, you can adjust the DestinationRectangle in the Render method:
class ChatSystem : public WrappedText {
public:
// ... previous code ...
void Render(SDL_Surface* DestinationSurface,
int ScrollOffset) {
SDL_Rect ScrolledRect =
DestinationRectangle;
ScrolledRect.y -= ScrollOffset;
SDL_BlitSurface(TextSurface, nullptr,
DestinationSurface,
&ScrolledRect);
}
};Input Handling
For user input, you can create an input box at the bottom of the chat:
class InputBox : public Text {
public:
InputBox(int FontSize, int MaxWidth) :
Text{FontSize}, MaxWidth{MaxWidth} {
CreateSurface("");
}
void AddCharacter(char c) {
Content += c;
CreateSurface(Content);
}
void RemoveCharacter() {
if (!Content.empty()) {
Content.pop_back();
CreateSurface(Content);
}
}
std::string GetContent() const {
return Content;
}
private:
std::string Content;
int MaxWidth;
};Remember to handle SDL keyboard events in your main loop to update the InputBox.
By combining these elements, you can create a responsive and efficient text-heavy UI. Be sure to optimize rendering by only updating the chat surface when new messages are added or when scrolling occurs, rather than every frame.
Text Performance, Fitting and Wrapping
Explore advanced techniques for optimizing and controlling text rendering when using SDL_ttf