blob: f9e1c4184eec93c81db1d445617ad3fedab4e769 [file] [log] [blame]
// Copyright 2021 The Wuffs Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------
/*
sdl-imageviewer is a simple GUI program for viewing an image. To run:
$CXX sdl-imageviewer.cc -lSDL2 -lSDL2_image && \
./a.out ../../test/data/bricks-color.png; rm -f a.out
for a C++ compiler $CXX, such as clang++ or g++.
The Tab key switches between decoding the image via Wuffs or via SDL2_image.
There should be no difference unless you uncomment the § line of code below.
The Escape key quits.
----
This program (in Wuffs' example directory) is like example/imageviewer but with
fewer features. It focuses on showing how to integrate the Wuffs image decoders
with SDL (as an alternative to the SDL_image extension).
While SDL is cross-platform, this program is not as good as example/imageviewer
for general use. SDL (which is designed for full-screen games) uses a noticable
amount of CPU (and therefore power) polling for events even when the program
isn't otherwise doing anything.
*/
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
// Wuffs ships as a "single file C library" or "header file library" as per
// https://github.com/nothings/stb/blob/master/docs/stb_howto.txt
//
// To use that single file as a "foo.c"-like implementation, instead of a
// "foo.h"-like header, #define WUFFS_IMPLEMENTATION before #include'ing or
// compiling it.
#define WUFFS_IMPLEMENTATION
// Defining the WUFFS_CONFIG__STATIC_FUNCTIONS macro is optional, but when
// combined with WUFFS_IMPLEMENTATION, it demonstrates making all of Wuffs'
// functions have static storage.
//
// This can help the compiler ignore or discard unused code, which can produce
// faster compiles and smaller binaries. Other motivations are discussed in the
// "ALLOW STATIC IMPLEMENTATION" section of
// https://raw.githubusercontent.com/nothings/stb/master/docs/stb_howto.txt
#define WUFFS_CONFIG__STATIC_FUNCTIONS
// Defining the WUFFS_CONFIG__MODULE* macros are optional, but it lets users of
// release/c/etc.c choose which parts of Wuffs to build. That file contains the
// entire Wuffs standard library, implementing a variety of codecs and file
// formats. Without this macro definition, an optimizing compiler or linker may
// very well discard Wuffs code for unused codecs, but listing the Wuffs
// modules we use makes that process explicit. Preprocessing means that such
// code simply isn't compiled.
#define WUFFS_CONFIG__MODULES
#define WUFFS_CONFIG__MODULE__ADLER32
#define WUFFS_CONFIG__MODULE__AUX__BASE
#define WUFFS_CONFIG__MODULE__AUX__IMAGE
#define WUFFS_CONFIG__MODULE__BASE
#define WUFFS_CONFIG__MODULE__BMP
#define WUFFS_CONFIG__MODULE__CRC32
#define WUFFS_CONFIG__MODULE__DEFLATE
#define WUFFS_CONFIG__MODULE__GIF
#define WUFFS_CONFIG__MODULE__LZW
#define WUFFS_CONFIG__MODULE__PNG
#define WUFFS_CONFIG__MODULE__ZLIB
// If building this program in an environment that doesn't easily accommodate
// relative includes, you can use the script/inline-c-relative-includes.go
// program to generate a stand-alone C file.
#include "../../release/c/wuffs-unsupported-snapshot.c"
// ----------------
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_render.h>
// --------
class Wuffs_Load_RW_Callbacks : public wuffs_aux::DecodeImageCallbacks {
public:
Wuffs_Load_RW_Callbacks() : m_surface(NULL) {}
~Wuffs_Load_RW_Callbacks() {
if (m_surface) {
SDL_UnlockSurface(m_surface);
SDL_FreeSurface(m_surface);
m_surface = NULL;
}
}
SDL_Surface* //
TakeSurface() {
if (!m_surface) {
return NULL;
}
SDL_UnlockSurface(m_surface);
SDL_Surface* ret = m_surface;
m_surface = NULL;
return ret;
}
private:
wuffs_base__pixel_format //
SelectPixfmt(const wuffs_base__image_config& image_config) override {
// Regardless of endianness, SDL_PIXELFORMAT_BGRA32 (from a few lines
// below) is equivalent to WUFFS_BASE__PIXEL_FORMAT__BGRA_NONPREMUL.
return wuffs_base__make_pixel_format(
WUFFS_BASE__PIXEL_FORMAT__BGRA_NONPREMUL);
}
AllocPixbufResult //
AllocPixbuf(const wuffs_base__image_config& image_config,
bool allow_uninitialized_memory) override {
if (m_surface) {
SDL_UnlockSurface(m_surface);
SDL_FreeSurface(m_surface);
m_surface = NULL;
}
uint32_t w = image_config.pixcfg.width();
uint32_t h = image_config.pixcfg.height();
if ((w > 0xFFFFFF) || (h > 0xFFFFFF)) {
return AllocPixbufResult("Wuffs_Load_RW_Callbacks: image is too large");
}
uint32_t sdl_pixelformat = SDL_PIXELFORMAT_BGRA32;
// (§) Uncomment this line of code to invert the BGRA/RGBA color order.
// This isn't a generally useful feature for an image viewer, but it should
// make it obvious, when pressing the TAB key, whether you're using the
// Wuffs (inverted) or SDL_image (correct) decoder.
//
// sdl_pixelformat = SDL_PIXELFORMAT_RGBA32;
m_surface = SDL_CreateRGBSurfaceWithFormat(
0, static_cast<int>(w), static_cast<int>(h), 32, sdl_pixelformat);
if (!m_surface) {
return AllocPixbufResult(
"Wuffs_Load_RW_Callbacks: SDL_CreateRGBSurface failed");
}
SDL_LockSurface(m_surface);
wuffs_base__pixel_buffer pixbuf;
wuffs_base__status status = pixbuf.set_interleaved(
&image_config.pixcfg,
wuffs_base__make_table_u8(static_cast<uint8_t*>(m_surface->pixels),
m_surface->w * 4, m_surface->h,
m_surface->pitch),
wuffs_base__empty_slice_u8());
if (!status.is_ok()) {
SDL_UnlockSurface(m_surface);
SDL_FreeSurface(m_surface);
m_surface = NULL;
return AllocPixbufResult(status.message());
}
return AllocPixbufResult(wuffs_aux::MemOwner(NULL, &free), pixbuf);
}
SDL_Surface* m_surface;
};
// --------
class Wuffs_Load_RW_Input : public wuffs_aux::sync_io::Input {
public:
Wuffs_Load_RW_Input(SDL_RWops* rw, bool take_ownership_of_rw)
: m_rw(rw), m_ownership(take_ownership_of_rw) {}
~Wuffs_Load_RW_Input() {
if (m_rw && m_ownership) {
m_rw->close(m_rw);
}
}
private:
std::string //
CopyIn(wuffs_aux::IOBuffer* dst) override {
if (!m_rw) {
return "Wuffs_Load_RW_Input: NULL SDL_RWops";
} else if (!dst) {
return "Wuffs_Load_RW_Input: NULL IOBuffer";
} else if (dst->meta.closed) {
return "Wuffs_Load_RW_Input: end of file";
}
dst->compact();
if (dst->writer_length() == 0) {
return "Wuffs_Load_RW_Input: full IOBuffer";
}
size_t n = m_rw->read(m_rw, dst->writer_pointer(), 1, dst->writer_length());
dst->meta.wi += n;
return std::string();
}
SDL_RWops* m_rw;
const bool m_ownership;
};
// --------
// Wuffs_Load_RW loads the image from the input rw. It is like SDL_image's
// IMG_Load_RW function but it returns any error in-band (as a std::string)
// instead of separately (global state accessible via SDL_GetError).
//
// On success, the SDL_Surface* returned will be non-NULL and the caller owns
// it. Ownership means that they are responsible for calling SDL_FreeSurface on
// it when done.
std::pair<SDL_Surface*, std::string> //
Wuffs_Load_RW(SDL_RWops* rw, bool take_ownership_of_rw) {
Wuffs_Load_RW_Callbacks callbacks;
Wuffs_Load_RW_Input input(rw, take_ownership_of_rw);
wuffs_aux::DecodeImageResult res = wuffs_aux::DecodeImage(callbacks, input);
if (!res.error_message.empty()) {
return std::make_pair<SDL_Surface*, std::string>(
NULL, std::move(res.error_message));
}
return std::make_pair<SDL_Surface*, std::string>(callbacks.TakeSurface(),
std::string());
}
// ----------------
SDL_Surface* g_image = NULL;
bool g_load_via_sdl_image = false;
bool //
draw(SDL_Window* window) {
SDL_Surface* ws = SDL_GetWindowSurface(window);
if (!ws) {
// Use an indirect approach, for exotic window pixel formats (e.g. X.org 10
// bits per RGB channel), when we can't get the window surface directly.
//
// See https://github.com/google/wuffs/issues/51
SDL_Renderer* r = SDL_CreateRenderer(window, -1, 0);
if (!r) {
fprintf(stderr, "main: SDL_CreateRenderer: %s\n", SDL_GetError());
return false;
}
SDL_RenderClear(r);
if (g_image) {
SDL_Texture* texture = SDL_CreateTextureFromSurface(r, g_image);
SDL_RenderCopy(r, texture, NULL, &g_image->clip_rect);
SDL_DestroyTexture(texture);
}
SDL_RenderPresent(r);
SDL_DestroyRenderer(r);
return true;
}
// Use a direct approach.
SDL_FillRect(ws, NULL, SDL_MapRGB(ws->format, 0x00, 0x00, 0x00));
if (g_image) {
SDL_BlitSurface(g_image, NULL, ws, NULL);
}
SDL_UpdateWindowSurface(window);
return true;
}
bool //
load_image(const char* filename) {
if (g_image) {
SDL_FreeSurface(g_image);
g_image = NULL;
}
SDL_RWops* rw = SDL_RWFromFile(filename, "rb");
if (!rw) {
fprintf(stderr, "main: SDL_RWFromFile(\"%s\"): %s\n", filename,
SDL_GetError());
return false;
}
constexpr bool take_ownership_of_rw = true;
if (g_load_via_sdl_image) {
g_image = IMG_Load_RW(rw, take_ownership_of_rw);
if (!g_image) {
fprintf(stderr, "main: IMG_Load_RW(\"%s\"): %s\n", filename,
SDL_GetError());
return false;
}
} else {
std::pair<SDL_Surface*, std::string> p =
Wuffs_Load_RW(rw, take_ownership_of_rw);
if (!p.second.empty()) {
fprintf(stderr, "main: Wuffs_Load_RW(\"%s\"): %s\n", filename,
p.second.c_str());
return false;
}
g_image = p.first;
}
return true;
}
int //
main(int argc, char** argv) {
if (argc != 2) {
fprintf(stderr, "usage: %s filename\n", argv[0]);
return 1;
}
if (SDL_Init(SDL_INIT_VIDEO) < 0) {
fprintf(stderr, "main: SDL_Init: %s\n", SDL_GetError());
return 1;
}
SDL_Window* window =
SDL_CreateWindow("sdl-imageviewer", SDL_WINDOWPOS_UNDEFINED,
SDL_WINDOWPOS_UNDEFINED, 1024, 768, SDL_WINDOW_SHOWN);
if (!window) {
fprintf(stderr, "main: SDL_CreateWindow: %s\n", SDL_GetError());
return 1;
}
if (!load_image(argv[1])) {
return 1;
}
while (true) {
SDL_Event event;
if (!SDL_WaitEvent(&event)) {
fprintf(stderr, "main: SDL_WaitEvent: %s\n", SDL_GetError());
return 1;
}
switch (event.type) {
case SDL_QUIT:
goto cleanup;
case SDL_WINDOWEVENT:
switch (event.window.event) {
case SDL_WINDOWEVENT_EXPOSED:
if (!draw(window)) {
return 1;
}
break;
}
break;
case SDL_KEYDOWN:
switch (event.key.keysym.sym) {
case SDLK_ESCAPE:
goto cleanup;
case SDLK_TAB:
g_load_via_sdl_image = !g_load_via_sdl_image;
printf("Switched to %s.\n",
g_load_via_sdl_image ? "SDL_image" : "Wuffs");
if (!load_image(argv[1]) || !draw(window)) {
return 1;
}
break;
}
break;
}
}
cleanup:
if (g_image) {
SDL_FreeSurface(g_image);
g_image = NULL;
}
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}