SDL Tutorial: Drawing Text with SDL.

SDL: Drawing text sample function.c

// TTF_Init() must be called before using this function.
// Remember to call TTF_Quit() when done.

void drawText
(SDL_Surface* screen, char* string,
int size, int x, int y,
int fR, int fG, int fB,
int bR, int bG, int bB)
{

TTF_Font* font = TTF_OpenFont("ARIAL.TTF", size);

SDL_Color foregroundColor = { fR, fG, fB };
SDL_Color backgroundColor = { bR, bG, bB };

SDL_Surface* textSurface
= TTF_RenderText_Shaded
(font, string, foregroundColor, backgroundColor);

SDL_Rect textLocation = { x, y, 0, 0 };

SDL_BlitSurface(textSurface, NULL, screen, &textLocation);

SDL_FreeSurface(textSurface);

TTF_CloseFont(font);

}

SDL: Drawing text sample program.c

#include "SDL.h"

#include "SDL_TTF.h"

const int WINDOW_WIDTH = 640;
const int WINDOW_HEIGHT = 480;

const char* WINDOW_TITLE = "SDL Start";


int main(int argc, char **argv)
{

SDL_Init( SDL_INIT_VIDEO );

TTF_Init();


SDL_Surface* screen 
= SDL_SetVideoMode
( WINDOW_WIDTH,
WINDOW_HEIGHT, 0,
SDL_HWSURFACE
| SDL_DOUBLEBUF );


SDL_WM_SetCaption( WINDOW_TITLE, 0 );

TTF_Font* font = TTF_OpenFont("ARIAL.TTF", 12);

SDL_Color foregroundColor = { 255, 255, 255 };
SDL_Color backgroundColor = { 0, 0, 255 };

SDL_Surface* textSurface = TTF_RenderText_Shaded(font, "This is my text.", foregroundColor, backgroundColor);

// Pass zero for width and height to draw the whole surface
SDL_Rect textLocation = { 100, 100, 0, 0 };

SDL_Event event;
bool gameRunning = true;


while (gameRunning)
{

	if (SDL_PollEvent(&event))
	{

		if (event.type == SDL_QUIT)
		{
		gameRunning = false;
		}

	}

SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 0, 0, 0));

SDL_BlitSurface(textSurface, NULL, screen, &textLocation);

SDL_Flip(screen);

}



SDL_FreeSurface(textSurface);

TTF_CloseFont(font);
TTF_Quit();

SDL_Quit();


return 0;
}

SDL: Drawing text tutorial

Drawing Text with SDL

Note: This tutorial assumes that you already know how to display a window and draw a
sprite with SDL.


Setting Up the SDL TrueType Font Library


To display text with SDL, you need the SDL_ttf library. You can download the library
here (For windows, grab SDL_ttfdevel2.0.7VC6.
zip). Once you've downloaded the file,
extract it to a folder of your choice.

You now need to tell your IDE where to find the SDL_ttf files. This is the same process as
telling SDL where to find the SDL files (remember the lib and include folders?). Since
I'm using Visual Studio .NET 2003, I'll go over how to set up SDL_ttf with that IDE.
Select Tools> Options.

Go to Projects in the left pane and select VC++ Directories. In
the Show directories for: menu, select Include files. Click the New Line button
(looks like a folder with a star behind it) and then click the ... button that appears.
Navigate to where you extracted the SDL_ttf files, highlight the include folder and click
Open.

Again, select Tools>
Options. Go to Projects in the left pane and select VC++
Directories. In the Show directories for: menu, select Library files. Click the New
Line button (looks like a folder with a star behind it) and then click the ... button that
appears. Navigate to where you extracted the SDL_ttf files, highlight the lib folder and
click Open.

Once you've created a project and added a C++ file to it, you need to go to Project>
Your Project Properties, click the Linker folder, and select Input. In Additional
Dependencies, you need to have "sdl.lib sdlmain.lib sdl_ttf.lib", without the quotes.

In the lib folder, under the folder where you extracted the SDL_ttf files, you'll find the
file "SDL_ttf.dll". Copy and paste this file into your project directory. When you distribute
your program, be sure to include this file in the same directory as the .exe.

The TrueType font library requires a font. Fonts come in font files. Click here to get the
font file for Arial. Put this file in your project directory.


Displaying Text with SDL_ttf

To display text, we first initialize SDL_ttf. We then create a surface that holds the text
and blit that surface to our screen buffer. Finally, we shut down SDL_ttf and free the text
surface.


Initializing SDL_ttf.

We initialize SDL_ttf with a call to TTF_Init(), which takes no parameters.
Creating a surface with some text on it.

To create a surface with the text we want to display, we call
TTF_RenderText_Shaded(), which takes four parameters and returns a pointer to an
SDL_Surface.

The first parameter to TTF_RenderText_Shaded() is a pointer to a TTF_Font
structure. We get this structure with a call to TTF_OpenFont(), which takes two
paramters and returns a pointer to a TTF_Font structure.

The first parameter to TTF_OpenFont() is the name of the file that contains the font information.

The second parameter is the size we want our text to be.

The second parameter to TTF_RenderText_Shaded() is the text we want displayed.

The third parameter is an SDL_Color structure that stores the foreground color of our
text.

The fourth parameter is an SDL_Color structure that stores the background color of
our text. The foreground color of the text you're reading right now is white; the
background color is dark blue (at least I think it is...apparently I'm partially color blind,
whatever that means).

The SDL_Color structure has three variables: a red value, a blue value, and a green
value.


Blitting the text surface.

Blitting the text surface is the same as blitting a sprite surface. The only difference is
that you'll usually want to blit the entire text surface. This means that you only need to
fill in an SDL_Rect structure for the location of the text on the screen. You can just pass
NULL to SDL_BlitSurface() for the source location.


Shutting down SDL_ttf.

SDL_ttf is shutdown with a call to TTF_Quit(), which takes no parameters.
You also have to free the memory that the TTF_Font structure is using. This is done with
a call to TTF_CloseFont().

Since we created a surface to store our text, we shouldn't forget to free it with a call to
SDL_FreeSurface().