我在使用 SDL_ttf 时遇到了问题，我是这种类型的库的新手，因此下面的代码来自https://www.libsdl.org/projects/SDL_ttf/release/SDL2_ttf-2.0.15.tar.gz->showfont.c
/*
showfont: An example of using the SDL_ttf library with 2D graphics.
Copyright (C) 2001-2019 Sam Lantinga <[email protected]>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
/* A simple program to test the text rendering feature of the TTF library */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "SDL2/SDL.h"
#include "SDL_ttf.h"
#define DEFAULT_PTSIZE 18
#define DEFAULT_TEXT "The quick brown fox jumped over the lazy dog"
#define WIDTH 640
#define HEIGHT 480
#define TTF_SHOWFONT_USAGE \
"Usage: %s [-solid] [-shaded] [-blended] [-utf8|-unicode] [-b] [-i] [-u] [-s] [-outline size] [-hintlight|-hintmono|-hintnone] [-nokerning] [-fgcol r,g,b,a] [-bgcol r,g,b,a] <font>.ttf [ptsize] [text]\n"
typedef enum
{
TextRenderSolid,
TextRenderShaded,
TextRenderBlended
} TextRenderMethod;
typedef struct {
SDL_Texture *caption;
SDL_Rect captionRect;
SDL_Texture *message;
SDL_Rect messageRect;
} Scene;
static void draw_scene(SDL_Renderer *renderer, Scene *scene)
{
/* Clear the background to background color */
SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0xFF);
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, scene->caption, NULL, &scene->captionRect);
SDL_RenderCopy(renderer, scene->message, NULL, &scene->messageRect);
SDL_RenderPresent(renderer);
}
static void cleanup(int exitcode)
{
TTF_Quit();
SDL_Quit();
exit(exitcode);
}
int main(int argc, char *argv[])
{
char *argv0 = argv[0];
SDL_Window *window;
SDL_Renderer *renderer;
TTF_Font *font;
SDL_Surface *text = NULL;
Scene scene;
int ptsize;
int i, done;
SDL_Color white = { 0xFF, 0xFF, 0xFF, 0 };
SDL_Color black = { 0x00, 0x00, 0x00, 0 };
SDL_Color *forecol;
SDL_Color *backcol;
SDL_Event event;
TextRenderMethod rendermethod;
int renderstyle;
int outline;
int hinting;
int kerning;
int dump;
enum {
RENDER_LATIN1,
RENDER_UTF8,
RENDER_UNICODE
} rendertype;
char *message, string[128];
/* Look for special execution mode */
dump = 0;
/* Look for special rendering types */
rendermethod = TextRenderShaded;
renderstyle = TTF_STYLE_NORMAL;
rendertype = RENDER_LATIN1;
outline = 0;
hinting = TTF_HINTING_NORMAL;
kerning = 1;
/* Default is black and white */
forecol = &black;
backcol = &white;
for (i=1; argv[i] && argv[i][0] == '-'; ++i) {
if (strcmp(argv[i], "-solid") == 0) {
rendermethod = TextRenderSolid;
} else
if (strcmp(argv[i], "-shaded") == 0) {
rendermethod = TextRenderShaded;
} else
if (strcmp(argv[i], "-blended") == 0) {
rendermethod = TextRenderBlended;
} else
if (strcmp(argv[i], "-utf8") == 0) {
rendertype = RENDER_UTF8;
} else
if (strcmp(argv[i], "-unicode") == 0) {
rendertype = RENDER_UNICODE;
} else
if (strcmp(argv[i], "-b") == 0) {
renderstyle |= TTF_STYLE_BOLD;
} else
if (strcmp(argv[i], "-i") == 0) {
renderstyle |= TTF_STYLE_ITALIC;
} else
if (strcmp(argv[i], "-u") == 0) {
renderstyle |= TTF_STYLE_UNDERLINE;
} else
if (strcmp(argv[i], "-s") == 0) {
renderstyle |= TTF_STYLE_STRIKETHROUGH;
} else
if (strcmp(argv[i], "-outline") == 0) {
if (sscanf (argv[++i], "%d", &outline) != 1) {
fprintf(stderr, TTF_SHOWFONT_USAGE, argv0);
return(1);
}
} else
if (strcmp(argv[i], "-hintlight") == 0) {
hinting = TTF_HINTING_LIGHT;
} else
if (strcmp(argv[i], "-hintmono") == 0) {
hinting = TTF_HINTING_MONO;
} else
if (strcmp(argv[i], "-hintnone") == 0) {
hinting = TTF_HINTING_NONE;
} else
if (strcmp(argv[i], "-nokerning") == 0) {
kerning = 0;
} else
if (strcmp(argv[i], "-dump") == 0) {
dump = 1;
} else
if (strcmp(argv[i], "-fgcol") == 0) {
int r, g, b, a = 0xFF;
if (sscanf (argv[++i], "%d,%d,%d,%d", &r, &g, &b, &a) < 3) {
fprintf(stderr, TTF_SHOWFONT_USAGE, argv0);
return(1);
}
forecol->r = (Uint8)r;
forecol->g = (Uint8)g;
forecol->b = (Uint8)b;
forecol->a = (Uint8)a;
} else
if (strcmp(argv[i], "-bgcol") == 0) {
int r, g, b, a = 0xFF;
if (sscanf (argv[++i], "%d,%d,%d,%d", &r, &g, &b, &a) < 3) {
fprintf(stderr, TTF_SHOWFONT_USAGE, argv0);
return(1);
}
backcol->r = (Uint8)r;
backcol->g = (Uint8)g;
backcol->b = (Uint8)b;
backcol->a = (Uint8)a;
} else {
fprintf(stderr, TTF_SHOWFONT_USAGE, argv0);
return(1);
}
}
argv += i;
argc -= i;
/* Check usage */
if (!argv[0]) {
fprintf(stderr, TTF_SHOWFONT_USAGE, argv0);
return(1);
}
/* Initialize the TTF library */
if (TTF_Init() < 0) {
fprintf(stderr, "Couldn't initialize TTF: %s\n",SDL_GetError());
SDL_Quit();
return(2);
}
/* Open the font file with the requested point size */
ptsize = 0;
if (argc > 1) {
ptsize = atoi(argv[1]);
}
if (ptsize == 0) {
i = 2;
ptsize = DEFAULT_PTSIZE;
} else {
i = 3;
}
font = TTF_OpenFont(argv[0], ptsize);
if (font == NULL) {
fprintf(stderr, "Couldn't load %d pt font from %s: %s\n",
ptsize, argv[0], SDL_GetError());
cleanup(2);
}
TTF_SetFontStyle(font, renderstyle);
TTF_SetFontOutline(font, outline);
TTF_SetFontKerning(font, kerning);
TTF_SetFontHinting(font, hinting);
if(dump) {
for(i = 48; i < 123; i++) {
SDL_Surface* glyph = NULL;
glyph = TTF_RenderGlyph_Shaded(font, i, *forecol, *backcol);
if(glyph) {
char outname[64];
SDL_snprintf(outname, sizeof(outname), "glyph-%d.bmp", i);
SDL_SaveBMP(glyph, outname);
}
}
cleanup(0);
}
/* Create a window */
if (SDL_CreateWindowAndRenderer(WIDTH, HEIGHT, 0, &window, &renderer) < 0) {
fprintf(stderr, "SDL_CreateWindowAndRenderer() failed: %s\n", SDL_GetError());
cleanup(2);
}
/* Show which font file we're looking at */
SDL_snprintf(string, sizeof(string), "Font file: %s", argv[0]); /* possible overflow */
switch (rendermethod) {
case TextRenderSolid:
text = TTF_RenderText_Solid(font, string, *forecol);
break;
case TextRenderShaded:
text = TTF_RenderText_Shaded(font, string, *forecol, *backcol);
break;
case TextRenderBlended:
text = TTF_RenderText_Blended(font, string, *forecol);
break;
}
if (text != NULL) {
scene.captionRect.x = 4;
scene.captionRect.y = 4;
scene.captionRect.w = text->w;
scene.captionRect.h = text->h;
scene.caption = SDL_CreateTextureFromSurface(renderer, text);
SDL_FreeSurface(text);
}
/* Render and center the message */
if (argc > 2) {
message = argv[2];
} else {
message = DEFAULT_TEXT;
}
switch (rendertype) {
case RENDER_LATIN1:
switch (rendermethod) {
case TextRenderSolid:
text = TTF_RenderText_Solid(font, message, *forecol);
break;
case TextRenderShaded:
text = TTF_RenderText_Shaded(font, message, *forecol, *backcol);
break;
case TextRenderBlended:
text = TTF_RenderText_Blended(font, message, *forecol);
break;
}
break;
case RENDER_UTF8:
switch (rendermethod) {
case TextRenderSolid:
text = TTF_RenderUTF8_Solid(font, message, *forecol);
break;
case TextRenderShaded:
text = TTF_RenderUTF8_Shaded(font, message, *forecol, *backcol);
break;
case TextRenderBlended:
text = TTF_RenderUTF8_Blended(font, message, *forecol);
break;
}
break;
case RENDER_UNICODE:
{
Uint16 *unicode_text = SDL_iconv_utf8_ucs2(message);
switch (rendermethod) {
case TextRenderSolid:
text = TTF_RenderUNICODE_Solid(font, unicode_text, *forecol);
break;
case TextRenderShaded:
text = TTF_RenderUNICODE_Shaded(font, unicode_text, *forecol, *backcol);
break;
case TextRenderBlended:
text = TTF_RenderUNICODE_Blended(font, unicode_text, *forecol);
break;
}
SDL_free(unicode_text);
}
break;
}
if (text == NULL) {
fprintf(stderr, "Couldn't render text: %s\n", SDL_GetError());
TTF_CloseFont(font);
cleanup(2);
}
scene.messageRect.x = (WIDTH - text->w)/2;
scene.messageRect.y = (HEIGHT - text->h)/2;
scene.messageRect.w = text->w;
scene.messageRect.h = text->h;
scene.message = SDL_CreateTextureFromSurface(renderer, text);
printf("Font is generally %d big, and string is %d big\n",
TTF_FontHeight(font), text->h);
draw_scene(renderer, &scene);
/* Wait for a keystroke, and blit text on mouse press */
done = 0;
while (!done) {
if (SDL_WaitEvent(&event) < 0) {
fprintf(stderr, "SDL_PullEvent() error: %s\n",
SDL_GetError());
done = 1;
continue;
}
switch (event.type) {
case SDL_MOUSEBUTTONDOWN:
scene.messageRect.x = event.button.x - text->w/2;
scene.messageRect.y = event.button.y - text->h/2;
scene.messageRect.w = text->w;
scene.messageRect.h = text->h;
draw_scene(renderer, &scene);
break;
case SDL_KEYDOWN:
case SDL_QUIT:
done = 1;
break;
default:
break;
}
}
SDL_FreeSurface(text);
TTF_CloseFont(font);
SDL_DestroyTexture(scene.caption);
SDL_DestroyTexture(scene.message);
cleanup(0);
/* Not reached, but fixes compiler warnings */
return 0;
}
/* vi: set ts=4 sw=4 expandtab: */
当我在 CodeBlocks 中构建时，它会给我以下构建日志：
g++ -L/usr/lib -o bin/Debug/a obj/Debug/main.o -lSDL2 -lSDL2_ttf -lSDL2 -lSDL2_ttf
/usr/lib/libSDL2_ttf.so: undefined reference to `SDL_RWclose'
/usr/lib/libSDL2_ttf.so: undefined reference to `SDL_RWread'
/usr/lib/libSDL2_ttf.so: undefined reference to `SDL_RWtell'
/usr/lib/libSDL2_ttf.so: undefined reference to `SDL_RWseek'
/usr/lib/libSDL2_ttf.so: undefined reference to `SDL_RWsize'
collect2: error: ld returned 1 exit status