我正在使用一个SDL_Window和SDL_Renderer。
是否可以将SDL_TTF与SDL_Render/SDL_Window一起使用？如果可以，应该怎么做？
7个回答
80
是的，只要你有一个渲染器和窗口，并且你不打算涉及表面操作，那么你可能想着创建纹理，这里有一个样例代码：
//this opens a font style and sets a size
TTF_Font* Sans = TTF_OpenFont("Sans.ttf", 24);
// this is the color in rgb format,
// maxing out all would give you the color white,
// and it will be your text's color
SDL_Color White = {255, 255, 255};
// as TTF_RenderText_Solid could only be used on
// SDL_Surface then you have to create the surface first
SDL_Surface* surfaceMessage =
TTF_RenderText_Solid(Sans, "put your text here", White);
// now you can convert it into a texture
SDL_Texture* Message = SDL_CreateTextureFromSurface(renderer, surfaceMessage);
SDL_Rect Message_rect; //create a rect
Message_rect.x = 0; //controls the rect's x coordinate
Message_rect.y = 0; // controls the rect's y coordinte
Message_rect.w = 100; // controls the width of the rect
Message_rect.h = 100; // controls the height of the rect
// (0,0) is on the top left of the window/screen,
// think a rect as the text's box,
// that way it would be very simple to understand
// Now since it's a texture, you have to put RenderCopy
// in your game loop area, the area where the whole code executes
// you put the renderer's name first, the Message,
// the crop size (you can ignore this if you don't want
// to dabble with cropping), and the rect which is the size
// and coordinate of your texture
SDL_RenderCopy(renderer, Message, NULL, &Message_rect);
// Don't forget to free your surface and texture
SDL_FreeSurface(surfaceMessage);
SDL_DestroyTexture(Message);
我尝试逐行解释代码，你在那里没有看到任何窗口，因为我已经假设你知道如何初始化渲染器，这会让我知道你也知道如何初始化窗口，然后你所需要的就是如何初始化纹理的想法。
这里有一些小问题，请问你的窗口打开了吗？它是黑色的吗？如果是，那么我的想法是正确的；如果不是，那么你可以问我，我可以更改此代码以实现由渲染器和窗口组成的整个部分。
- kdyz
15
24
SDL_ttf 最简单可运行示例
虽然不是很高效，但易于集成。如果要提高效率，请参阅：如何高效地使用 SDL2 渲染字体和文本？
这个库与主要的 SDL 源代码分开存储在一个单独的仓库中，但是托管在同一个官方服务器上，所以应该没问题：http://hg.libsdl.org/SDL_ttf/
换行符不起作用。您需要使用行高来处理。
编译和运行：
sudo apt-get install -y libsdl2-dev
gcc -lSDL2 -lSDL2_ttf -o ttf ttf.c
./ttf /usr/share/fonts/truetype/freefont/FreeMonoOblique.ttf
你需要向程序传递一个TTF字体文件的路径。
ttf.c
#include <stdlib.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_ttf.h>
#define WINDOW_WIDTH 300
#define WINDOW_HEIGHT (WINDOW_WIDTH)
/*
- x, y: upper left corner.
- texture, rect: outputs.
*/
void get_text_and_rect(SDL_Renderer *renderer, int x, int y, char *text,
TTF_Font *font, SDL_Texture **texture, SDL_Rect *rect) {
int text_width;
int text_height;
SDL_Surface *surface;
SDL_Color textColor = {255, 255, 255, 0};
surface = TTF_RenderText_Solid(font, text, textColor);
*texture = SDL_CreateTextureFromSurface(renderer, surface);
text_width = surface->w;
text_height = surface->h;
SDL_FreeSurface(surface);
rect->x = x;
rect->y = y;
rect->w = text_width;
rect->h = text_height;
}
int main(int argc, char **argv) {
SDL_Event event;
SDL_Rect rect1, rect2;
SDL_Renderer *renderer;
SDL_Texture *texture1, *texture2;
SDL_Window *window;
char *font_path;
int quit;
if (argc == 1) {
font_path = "FreeSans.ttf";
} else if (argc == 2) {
font_path = argv[1];
} else {
fprintf(stderr, "error: too many arguments\n");
exit(EXIT_FAILURE);
}
/* Inint TTF. */
SDL_Init(SDL_INIT_TIMER | SDL_INIT_VIDEO);
SDL_CreateWindowAndRenderer(WINDOW_WIDTH, WINDOW_WIDTH, 0, &window, &renderer);
TTF_Init();
TTF_Font *font = TTF_OpenFont(font_path, 24);
if (font == NULL) {
fprintf(stderr, "error: font not found\n");
exit(EXIT_FAILURE);
}
get_text_and_rect(renderer, 0, 0, "hello", font, &texture1, &rect1);
get_text_and_rect(renderer, 0, rect1.y + rect1.h, "world", font, &texture2, &rect2);
quit = 0;
while (!quit) {
while (SDL_PollEvent(&event) == 1) {
if (event.type == SDL_QUIT) {
quit = 1;
}
}
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);
SDL_RenderClear(renderer);
/* Use TTF textures. */
SDL_RenderCopy(renderer, texture1, NULL, &rect1);
SDL_RenderCopy(renderer, texture2, NULL, &rect2);
SDL_RenderPresent(renderer);
}
/* Deinit TTF. */
SDL_DestroyTexture(texture1);
SDL_DestroyTexture(texture2);
TTF_Quit();
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
return EXIT_SUCCESS;
}
在Ubuntu 16.04和SDL 2.0.4下测试通过。
- Ciro Santilli OurBigBook.com
15
没错。你可以用想要的文本创建一个表面(surface)，然后将其转换为纹理(texture)，以便进行渲染。
以下是我其中一个项目的示例代码：
std::string score_text = "score: " + std::to_string(score);
SDL_Color textColor = { 255, 255, 255, 0 };
SDL_Surface* textSurface = TTF_RenderText_Solid(font, score_text.c_str(), textColor);
SDL_Texture* text = SDL_CreateTextureFromSurface(renderer, textSurface);
int text_width = textSurface->w;
int text_height = textSurface->h;
SDL_FreeSurface(textSurface);
SDL_Rect renderQuad = { 20, win_height - 30, text_width, text_height };
SDL_RenderCopy(renderer, text, NULL, &renderQuad);
SDL_DestroyTexture(text);
假设你已经正确地初始化了SDL_ttf并加载了字体。 在示例中，score是一个整数。屏幕被清除并渲染到其他地方（我没有包括这部分）。
有关完整的工作示例，请查看Lazy Foo上SDL2中SDL_ttf的教程。
- jpw
4
这个出现未处理的内存异常是出于某个原因吗？ - Ethan Webster
@EthanWebster 噢，这段代码只是一个（不可运行的）示例，缺少必要的内容，比如初始化代码、错误检查等等。 - jpw
即使文本每帧都会改变，这是否高效？ - Damian Yerrick
并不真正兼容我现有的使用SDL_BlitScaled的代码，而且字体渲染得很糟糕。 - Phil
5
为了更易于理解，我们进行了编辑。使用Roboto.ttf (https://fonts.google.com/specimen/Roboto) 替换 Verdana.ttf，并添加了not2qubit建议。请记住，这完全不遵循任何C++类约定。我只是想确保这个内容容易复制/粘贴并运行。
要构建此代码，您需要添加库SDL_ttf (https://www.libsdl.org/projects/SDL_ttf/)。
g++ demo.cpp -o demo -Wall -I include -lsdl2 -lsdl2_ttf
由于有些人在处理更复杂的代码时遇到困难，我在这里提供我的代码片段以帮助像我一样的初学者。这将只显示一个红色屏幕和黑色的“Hello World”。不要忘记在构建过程中添加 -lsdl2 和 -lsdl2_ttf，并在相同的文件夹中包含Verdana.ttf字体。
#include <iostream>
#include <SDL2/SDL.h>
#include <SDL2/SDL_ttf.h> //This is an sample library not included with stock SDL2. https://www.libsdl.org/projects/SDL_ttf/release-1.2.html
const char* WINDOW_TITLE = "Hello World SDL2 + TTF";
const char* FONT_NAME = "roboto.ttf";
const int FONT_SIZE = 128;
const int WINDOW_WIDTH = 1280, WINDOW_HEIGHT = 720;
SDL_Window* Window; // Window created by SDL.
SDL_Renderer* Renderer; // The renderer that shows our textures.
SDL_Event WindowEvent; // Event capturer from SDL Window.
SDL_Color TextColor = { 255, 0, 0, 255}; // Red SDL color.
TTF_Font* Font; // The font to be loaded from the ttf file.
SDL_Surface* TextSurface; // The surface necessary to create the font texture.
SDL_Texture* TextTexture; // The font texture prepared for render.
SDL_Rect TextRect; // Text rectangle area with the position for the texture text.
void CreateWindow() {
Window = SDL_CreateWindow(WINDOW_TITLE, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, WINDOW_WIDTH, WINDOW_HEIGHT, SDL_WINDOW_ALLOW_HIGHDPI);
if (!Window)
std::cout << "There was a problem creating the window.";
Renderer = SDL_CreateRenderer(Window, -1, 0);
if (!Renderer)
std::cout << "There was a problem creating the renderer.";
}
void CreateText(const char* Message) {
TTF_Init();
TTF_Font *font = TTF_OpenFont(FONT_NAME, FONT_SIZE);
if (!font)
std::cout << "Couldn't find/init open ttf font." << std::endl;
TextSurface = TTF_RenderText_Solid(font, Message, TextColor);
TextTexture = SDL_CreateTextureFromSurface(Renderer, TextSurface);
TextRect.x = WINDOW_WIDTH - TextSurface->w * 0.5; // Center horizontaly
TextRect.y = WINDOW_HEIGHT - TextSurface->h * 0.5; // Center verticaly
TextRect.w = TextSurface->w;
TextRect.h = TextSurface->h;
// After you create the texture you can release the surface memory allocation because we actually render the texture not the surface.
SDL_FreeSurface(TextSurface);
TTF_Quit();
}
bool IsPollingEvent() {
while(SDL_PollEvent(&WindowEvent)) {
switch (WindowEvent.type) {
case SDL_QUIT: return false;
}
}
return true;
}
void RenderText() {
SDL_SetRenderDrawColor(Renderer, 0, 0, 0, 255); // Make window bg black.
SDL_RenderClear(Renderer); // Paint screen black.
SDL_RenderCopy(Renderer, TextTexture, NULL, &TextRect); // Add text to render queue.
SDL_RenderPresent(Renderer); // Render everything that's on the queue.
SDL_Delay(10); // Delay to prevent CPU overhead as suggested by the user `not2qubit`
}
void ClearMemory() {
SDL_DestroyTexture(TextTexture);
SDL_DestroyRenderer(Renderer);
SDL_DestroyWindow(Window);
SDL_Quit();
std::cout << "Clear proccess done." << std::endl;
}
int main() {
CreateWindow();
CreateText("Hello SDL_Ttf");
while (IsPollingEvent()) {
RenderText();
}
ClearMemory();
return EXIT_SUCCESS;
}
- Bruno Myrrha
1
如果您想使用class实现：
// Include somewhere
#include <SDL2/SDL_ttf.h>
// Do not forget to init TTF once somewhere main.cpp
if (TTF_Init()==-1) {
printf("Failed to TTF: %s", SDL_GetError());
return 1;
}
// Have a font instance ready
TTF_Font* font = TTF_OpenFont("assets/fonts/ugly.ttf", 72);
if (font==NULL){
printf("Failed to load font: %s", SDL_GetError());
}
// Have a Text instance ready
// (Class file is below this code)
// Also you need to provide SDL_Renderer* renderer to init
Text* fps_tracker = new Text(renderer, font);
// Somewhere in while true
fps_tracker.setText("FPS: 232");
// Render it
fps_tracker.render();
这是一个类：
using namespace std;
#include <string>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_ttf.h>
class Text {
SDL_Texture* texture = NULL;
SDL_Rect position;
TTF_Font* font;
SDL_Renderer* renderer;
SDL_Color color;
string text;
public:
Text(SDL_Renderer* renderer, TTF_Font* font, string text="", int x=0, int y=0, SDL_Color color={255, 255, 255}) {
position.x = x;
position.y = y;
this->color = color;
this->font = font;
this->renderer = renderer;
}
void setText(string text) {
if (this->text==text){
return;
}
this->text = text;
SDL_DestroyTexture(texture);
SDL_Surface* surface = TTF_RenderText_Solid(font, text.c_str(), color);
if (surface==NULL) {
printf("Failed to render text: %s", SDL_GetError());
}
position.w = surface->w;
position.h = surface->h;
texture = SDL_CreateTextureFromSurface(renderer, surface);
SDL_FreeSurface(surface);
}
void render() {
SDL_RenderCopy(renderer, texture, NULL, &position);
}
~Text() {
SDL_DestroyTexture(texture);
}
};
- BIOHAZARD
1
针对Windows上的Powershell
如果你正在尝试从Windows上的Powershell执行此操作，你很快就会发现这真是个麻烦事。直到现在...
当你想要坚持使用Clang++和SDL2渲染一个本地的Windows窗口和文本时，我刚刚花了几个小时来调试所有细节使其正常工作。
有三件事情你需要安装：LLVM, SDL2, SDL2_ttf。然后你必须确保你的程序可以找到你的库、头文件和字体。这基本上总结在以下程序here中:
//---------------------------------------------------------------------
// Name: HelloSDL2.cpp
// Author: EAML
// Date: 2021-05-16
//
// Description:
// A minimal PoC for producing a native SDL2 Windows app that can
// be ran from either Windows Explorer or from Powershell console.
// It's designed to use minimal command line, compiler options,
// and dependencies... It will display a gray window for 2 sec's.
//
// Dependencies:
// [1] LLVM Clang++ compiler package
// [2] SDL2 Libraries (DLL's) and Header files (*.h)
// [3] TTF Libraries (DLL's) and Header files (*.h)
//
// Notes:
// There is a slight variation in the bahaviour, depending on:
// (a) if you compile as a Windows GUI: the text will not show.
// (b) if you compile as a console CLI: text will show in both terminal and/or in a 2nd new window
// (c) You may need to use "main()" for console and "WinMain()" for GUI...
// (c) to install on Linux, use packages: clang, libsdl2-dev
// (d) Someone said: #define SDL_MAIN_HANDLED ...
//
// To Run:
// cp .\SDL2\lib\x64\SDL2.dll C:\Windows\. # For SDL2
// cp .\SDL2_ttf\lib\x64\*.dll C:\Windows\. # For SDL2 TTF
// cp C:\Windows\Fonts\arial.ttf . # Get a font...
//
// For a CLI version, with console output in 2nd Window:
// # clang++.exe -std=c++11 main.cpp -o main.exe -L .\SDL2\lib\x64\ -L .\SDL2_ttf\lib\x64\ -I .\SDL2_ttf\include\ -I .\SDL2\include\ -lShell32 -lSDL2main -lSDL2 -lSDL2_ttf -Wno-narrowing -Xlinker /subsystem:console
//
// For a GUI version, without any console output:
// # clang++.exe -std=c++11 main.cpp -o main.exe -L .\SDL2\lib\x64\ -L .\SDL2_ttf\lib\x64\ -I .\SDL2_ttf\include\ -I .\SDL2\include\ -lShell32 -lSDL2main -lSDL2 -lSDL2_ttf -Wno-narrowing -Xlinker /subsystem:windows
//
// References:
// [1] https://github.com/llvm/llvm-project/releases
// [2] http://www.libsdl.org/release/SDL2-devel-2.0.14-VC.zip
// [3] https://www.libsdl.org/projects/SDL_ttf/release/SDL2_ttf-devel-2.0.15-VC.zip
// [4] https://www.libsdl.org/projects/SDL_ttf/docs/SDL_ttf.html
// [5] http://www.sdltutorials.com/sdl-ttf
//---------------------------------------------------------------------
//#include <SDL2/SDL.h>
#include "SDL2/include/SDL.h"
#include "SDL2_ttf/include/SDL_ttf.h"
#include <stdio.h>
#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480
#define WINDOW_TITLE "Hello SDL2!"
//#define WINDOW_TEXT "Hello World!"
void drawText ( SDL_Surface* screen, char* string, int size, int x, int y, SDL_Color fgC, SDL_Color bgC) {
// Remember to call TTF_Init(), TTF_Quit(), before/after using this function.
TTF_Font* font = TTF_OpenFont("arial.ttf", size);
if(!font) {
printf("[ERROR] TTF_OpenFont() Failed with: %s\n", TTF_GetError());
exit(2);
}
TTF_SetFontStyle(font, TTF_STYLE_BOLD);
//SDL_Surface* textSurface = TTF_RenderText_Solid(font, string, fgC);
SDL_Surface* textSurface = TTF_RenderText_Shaded(font, string, fgC, bgC);
SDL_Rect textLocation = { x, y, 0, 0 };
SDL_BlitSurface(textSurface, NULL, screen, &textLocation);
SDL_FreeSurface(textSurface);
TTF_CloseFont(font);
//printf("Oh My Goodness, an error : %s\n", TTF_GetError()); return 1;
}
int main(int argc, char* args[]) {
SDL_Window* window = NULL; // The window we are rendering to
SDL_Surface* screenSurface = NULL; // The surface contained by the window
if (SDL_Init(SDL_INIT_VIDEO) < 0) {
printf( "SDL could not initialize! SDL Error: %s\n", SDL_GetError());
return 1;
}
window = SDL_CreateWindow(WINDOW_TITLE, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
if (window == NULL) {
printf( "Window could not be created! SDL Error: %s\n", SDL_GetError());
return 1;
}
screenSurface = SDL_GetWindowSurface(window);
SDL_FillRect(screenSurface, NULL, SDL_MapRGB(screenSurface->format, 0x80, 0x80, 0x80)); // Set a gray background canvas
SDL_UpdateWindowSurface(window);
//-----------------------------------------------------
// Draw the Text
//-----------------------------------------------------
if(TTF_Init() == -1) {
printf("[ERROR] TTF_Init() Failed with: %s\n", TTF_GetError());
exit(2);
}
SDL_Color fgC1 = { 0xff,0xff,0xff }, bgC1 = {0x00,0x00,0xa0}; // white text on blue background
SDL_Color fgC2 = { 0x00,0x00,0x00 }, bgC2 = {0xff,0x00,0xff}; // black text on magenta background
drawText( screenSurface, (char*) "Hello World! @ (x=50, y=100)", 18, 50,100, fgC1, bgC1); // 18 pt @ (x=100,y=150)
drawText( screenSurface, (char*) "arial.ttf @ (x=200, y=150)", 16, 200,150, fgC2, bgC2); // 16 pt @ (x=100,y=150)
SDL_UpdateWindowSurface(window);
TTF_Quit();
//-----------------------------------------------------
// Get some info...
//-----------------------------------------------------
SDL_version compiled;
SDL_version linked;
SDL_version ttfv;
SDL_VERSION(&compiled);
SDL_GetVersion(&linked);
SDL_TTF_VERSION(&ttfv);
printf("Compiled using SDL version : %d.%d.%d \n", compiled.major, compiled.minor, compiled.patch);
printf("and linked with SDL version : %d.%d.%d \n", linked.major, linked.minor, linked.patch);
printf("and using SDL_TTF version : %d.%d.%d \n", ttfv.major, ttfv.minor, ttfv.patch);
SDL_Delay(3000); // Wait 3 seconds
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
上述代码的运行结果如下：
如何达到这一点？
-
- 勾选
[x] 添加到Windows PATH。
- 勾选
如果您没有将LLVM添加到Windows PATH中，则至少暂时手动添加它。
- 打开PowerShell并键入：
$env:path += ";C:\Program Files\LLVM\bin"
- 打开PowerShell并键入：
为Windows安装SDL2： 下载并提取SDL2和SDL2_ttf运行时二进制文件（*.dll）和头文件库（在[2,3]中找到） 并将它们放入与C++文件相同的目录中的单独的SDL文件夹中。
现在您应该有类似于以下内容：
# tree --dirsfirst ./SDL2{,_ttf} -P *.h
./SDL2
├── include
│ ├── begin_code.h
│ ├── close_code.h
│ ├── SDL.h
│ ├── SDL_assert.h
...
│ ├── SDL_version.h
│ ├── SDL_video.h
│ └── SDL_vulkan.h
└── lib
./SDL2_ttf
└── include
└── SDL_ttf.h
# tree --dirsfirst ./SDL2{,_ttf}/lib -P *.dll
./SDL2/lib
├── x64
│ └── SDL2.dll
└── x86
└── SDL2.dll
./SDL2_ttf/lib
├── x64
│ ├── libfreetype-6.dll
│ ├── SDL2_ttf.dll
│ └── zlib1.dll
└── x86
├── libfreetype-6.dll
├── SDL2_ttf.dll
└── zlib1.dll
将所有相关的已下载DLL文件复制到C:\Windows\目录下，除非你知道如何让clang++.exe能够找到它们。（我没有成功...）
cd C:\path\to\main.cpp
cp .\SDL2\lib\x64\SDL2.dll C:\Windows\. # For SDL2
cp .\SDL2_ttf\lib\x64\*.dll C:\Windows\. # For SDL2 TTF
cp C:\Windows\Fonts\arial.ttf . # Get a font...
下载上述SDL2“Hello World” Windows程序。
- 使用这里的Minimal PoC代码。
使用以下命令编译程序：
clang++.exe -std=c++11 main2.cpp -o main.exe -L .\SDL2\lib\x64\ -L .\SDL2_ttf\lib\x64\ -I .\SDL2_ttf\include\ -I .\SDL2\include\ -lShell32 -lSDL2main -lSDL2 -lSDL2_ttf -Wno-narrowing -Xlinker /subsystem:windows
库的放置顺序似乎很重要。请确保按照上述顺序进行。
另外，注意两个不同的-Xlinker选项：
/subsystem:windows # This give you only one window but no console output
/subsystem:console # This give you console output, but in a 2nd window when in GUI
要查看其他链接器选项，请使用：
link.exe /link
link.exe /lib
# The most relevant are:
/DLL
/ENTRY:symbol
/LIBPATH:dir
/MACHINE:{ARM|ARM64|EBC|X64|X86}
/SUBSYSTEM:{CONSOLE | NATIVE | POSIX | WINDOWS | WINDOWSCE |...}
/VERBOSE
你现在可以开始了！
下载参考资料
- not2qubit
0
如果您不想或无法使用SDL2 TTF库，您可以仅使用freetype库轻松实现它。
包含freetype
#include <ft2build.h>
#include FT_FREETYPE_H
创建纹理类
class texture
{
public:
texture() : t{nullptr} {}
texture(const texture &) = delete;
texture &operator=(const texture &) = delete;
texture(texture &&o) : t{o.t}
{
o.t = nullptr;
}
inline texture &operator=(texture &&o)
{
release();
t = o.t;
o.t = nullptr;
return *this;
}
inline texture(SDL_Renderer *renderer, void *image, int width, int height, int depth, int pitch, uint32_t rmask, uint32_t gmask, uint32_t bmask, uint32_t amask) : t{nullptr}
{
attach_image(renderer, image, width, height, depth, pitch, rmask, gmask, bmask, amask);
}
inline void attach_image(SDL_Renderer *renderer, void *image, int width, int height, int depth, int pitch, uint32_t rmask, uint32_t gmask, uint32_t bmask, uint32_t amask)
{
release();
SDL_Surface *s = SDL_CreateRGBSurfaceFrom(image, width, height, depth, pitch, rmask, gmask, bmask, amask);
t = SDL_CreateTextureFromSurface(renderer, s);
SDL_FreeSurface(s);
}
inline void draw(SDL_Renderer *renderer, const SDL_Rect *src, const SDL_Rect *dest) const
{
if (t)
SDL_RenderCopyEx(renderer, t, src, dest, 0, nullptr, SDL_FLIP_NONE);
}
int width() const
{
if(!t) return 0;
int w;
SDL_QueryTexture(t, nullptr, nullptr, &w, nullptr);
return w;
}
int height() const {
if(!t) return 0;
int h;
SDL_QueryTexture(t, nullptr, nullptr, nullptr, &h);
return h;
}
~texture()
{
release();
}
private:
SDL_Texture *t;
inline void release()
{
if (t)
SDL_DestroyTexture(t);
t = nullptr;
}
};
创建字形类
struct character : texture
{
using texture::texture;
unsigned int advance;
int bearing_x;
int bearing_y;
};
确定字节序并设置掩码
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
#define rmask 0x000000ff
#define gmask 0x0000ff00
#define bmask 0x00ff0000
#define amask 0xff000000
#else
#define rmask 0xff000000
#define gmask 0x00ff0000
#define bmask 0x0000ff00
#define amask 0x000000ff
#endif
创建从FreeType的8位像素深度到SDL2的32位转换器
void convert_8_to_32_depth(std::vector<uint32_t> &res, unsigned char *image, int width, int height)
{
res.clear();
res.reserve(width * height);
for (int y = 0; y < height; ++y)
{
for (int x = 0; x < width; ++x)
{
if (image[y * width + x])
res.push_back(amask);
else
res.push_back(0);
}
}
}
创建字体存储纹理类
struct lib
{
lib() = default;
lib(SDL_Renderer *renderer, int height)
{
init(renderer, height);
}
void init(SDL_Renderer *renderer, int height)
{
FT_Library ft;
if (FT_Init_FreeType(&ft))
{
std::cout << "Can't init freetype lib\n";
}
FT_Face face;
//use if you have font data in array
// if (FT_New_Memory_Face(ft, font_array, std::size(font_array), 0, &face))
// {
// std::cout << "Failed to load font\n";
// }
if (FT_New_Face(ft, "location/to/my/font.ttf", 0, &face))
{
std::cout << "Failed to load font\n";
}
//set size of future glyphs
FT_Set_Pixel_Sizes(face, 0, height);
std::vector<uint32_t> image;
for (unsigned int c = 0; c < 256; ++c)
{
//load freetype glyph
if (FT_Load_Char(face, c, FT_LOAD_RENDER))
{
std::cout << "failed to load glyph\n";
}
if (face->glyph->bitmap.width)
{
///get image data that works for sdl2
convert_8_to_32_depth(image, face->glyph->bitmap.buffer, face->glyph->bitmap.width, face->glyph->bitmap.rows);
chars[c].attach_image(renderer, image.data(), face->glyph->bitmap.width, face->glyph->bitmap.rows,
32, face->glyph->bitmap.width * sizeof(decltype(image)::value_type),
rmask, gmask, bmask, amask);
}
chars[c].bearing_x = face->glyph->bitmap_left;
chars[c].bearing_y = face->glyph->bitmap_top;
chars[c].advance = face->glyph->advance.x;
}
FT_Done_Face(face);
FT_Done_FreeType(ft);
}
character chars[256];
};
打印文本函数
void print_text(SDL_Renderer *renderer, int x, int y, int height, std::string_view text)
{
static constexpr int default_height = 50;
//store map of each renderer used to avoid creating more libs than neccesary
static std::map<SDL_Renderer *, lib> l;
const lib& ts = l.try_emplace(renderer, renderer, default_height).first->second;
float scale = height / default_height;
SDL_Rect dest;
for (auto c : text)
{
dest.x = x + ts.chars[c].bearing_x * scale;
dest.y = y - ts.chars[c].bearing_y * scale;
dest.w = ts.chars[c].width() * scale;
dest.h = ts.chars[c].height() * scale;
ts.chars[c].draw(renderer, nullptr, &dest);
x += (ts.chars[c].advance >> 6) * scale;
}
}
- Jcsq6
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原文链接
原文链接
TTF_SizeText(TTF_Font *font, const char *text, int *w, int *h)函数获取渲染文本的尺寸。 - UnicornTTF_Init()。 - Keatinge