Change FONT SIZE of already existing TTF font in SDL.

[bryan177mcsc]

Hey guys I'm trying to do something quite simple, but I couldn't find any functions here http://www.libsdl.org/projects/SDL_ttf/docs/SDL_ttf.html to help me achieve that.

I have a menu class which will be taking care of basically all of the non-play part of a game I'm making. I'm trying to cut down on having to load many textures, so I've used polymorphism to have my sprite class re-use textures that have been previously loaded. I tried to the same with my text class but ran into some issues....

The problem is the following:

TTF_Font* the_font // in header

text::text(std::string passed_message, std::string font_location, int size, SDL_Color f_passed_color, SDL_Color b_passed_color, SDL_Renderer* passed_renderer)
{   
	//do stuff

	the_font = TTF_OpenFont(font_location.c_str(), size);  /* issue here */
	text_surface = TTF_RenderText_Solid(the_font, passed_message.c_str(),
        background_Color);
	text_texture = SDL_CreateTextureFromSurface(renderer, text_surface);
	SDL_FreeSurface(text_surface);
	
	//location stuff

}

This is the basic constructor, as you can see it will create a font by loading in the font from a file. I feel like that is a waste of resources. I would like to have another constructor which re-uses the same file. The problem is, by passing a previous font as an argument, I lose the ability to decide what size the font will be.

text::text(std::string passed_message, TTF_Font* passed_font, int size, SDL_Color f_passed_color, SDL_Color b_passed_color, SDL_Renderer* passed_renderer)
{   
	//do stuff

	the_font = passed_font;  /* issue here */ 
        /* Now int size has become irrelevant */
	text_surface = TTF_RenderText_Solid(the_font, passed_message.c_str(),
        background_Color);
	text_texture = SDL_CreateTextureFromSurface(renderer, text_surface);
	SDL_FreeSurface(text_surface);
	
	//location stuff

}

How can I edit the current existing font's size without loading a new font? Or using TTF_OpenFont()?

[Precious roy]

I dont really have time to to make a working example for you but here is my font/textbox class that you can use

font class

#pragma once
#include <assert.h>
#include <SDL_ttf.h>
#include <map>

class SDL_Font
{
	std::string FontLocation;
	std::map<int, TTF_Font*> FontSizes;

public:
        //Save the path to the TTF file and do some error checking string cant be empty
	bool Load(const std::string& FileLocation) override
	{
		FontLocation = FileLocation;
		
		if (FileLocation == "")
			assert(false);

		return true;
	}

        // loads and returns a TTF_Font.
        // looks in the map if the font already exists if not create a new font with the requested size
	TTF_Font* GetFont(int FontSize)
	{
		std::map<int, TTF_Font*>::iterator it;
		it = FontSizes.find(FontSize);

		if (it != FontSizes.end())
			return it->second;
		else
		{
			TTF_Font* mFont = TTF_OpenFont(FontLocation.c_str(), FontSize);
			FontSizes.insert(std::pair<int, TTF_Font*>(FontSize, mFont));
			return mFont;
		}		
	}

	~SDL_Font()
	{
		//i think i should delete the loaded fonts
	}
};

and draw text function

//Render the text to a SDL_Texture with the requested size.
void TextBox::RenderTexture()
{
	if (mText != "" && mFont != nullptr)
	{
		if (mTextTexture != nullptr)
			SDL_DestroyTexture(mTextTexture);//get rid of old texture(text)

                //Text Texture is made into a surface here
		SDL_Surface* mTextSurface = TTF_RenderText_Solid(mFont->GetFont(mFontSize),
			mText.c_str(),
			mColor);

		std::string temp = TTF_GetError(); //the text can not be emty

		mTextTextureSize.Width = mTextSurface->w;
		mTextTextureSize.Height = mTextSurface->h;

                //now the surface becomes a SDL_Texture i can now draw it to screen.
		mTextTexture = SDL_CreateTextureFromSurface(TheScreen::Instance().GetRenderer(), mTextSurface);

		SDL_FreeSurface(mTextSurface);
	}
}

hope that helps you

[bryan177mcsc]

I'm having trouble understanding this class sorry.

:(

[Precious roy]

hehe ok,

Note: this is old code and is not the best way of drawing text but it works and you should be able to get something useful from it.

i added comments to the code