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testsAndMisc-archive/C/imageViewer/main.c

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C
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#define WINDOW_WIDTH 800
#define WINDOW_HEIGHT 600
#define MAX_PATH_LEN 512
typedef struct {
SDL_Window* window;
SDL_Renderer* renderer;
SDL_Texture* texture;
char current_file[MAX_PATH_LEN];
int image_width;
int image_height;
float zoom_factor;
int offset_x;
int offset_y;
int dragging;
int last_mouse_x;
int last_mouse_y;
} ImageViewer;
int init_viewer(ImageViewer* viewer) {
if (SDL_Init(SDL_INIT_VIDEO) < 0) {
printf("SDL could not initialize! SDL_Error: %s\n", SDL_GetError());
return 0;
}
int img_flags = IMG_INIT_JPG | IMG_INIT_PNG;
if (!(IMG_Init(img_flags) & img_flags)) {
printf("SDL_image could not initialize! SDL_image Error: %s\n", IMG_GetError());
SDL_Quit();
return 0;
}
viewer->window = SDL_CreateWindow("JPG Image Viewer",
SDL_WINDOWPOS_UNDEFINED,
SDL_WINDOWPOS_UNDEFINED,
WINDOW_WIDTH,
WINDOW_HEIGHT,
SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE);
if (!viewer->window) {
printf("Window could not be created! SDL_Error: %s\n", SDL_GetError());
IMG_Quit();
SDL_Quit();
return 0;
}
viewer->renderer = SDL_CreateRenderer(viewer->window, -1, SDL_RENDERER_ACCELERATED);
if (!viewer->renderer) {
printf("Renderer could not be created! SDL_Error: %s\n", SDL_GetError());
SDL_DestroyWindow(viewer->window);
IMG_Quit();
SDL_Quit();
return 0;
}
viewer->texture = NULL;
viewer->current_file[0] = '\0';
viewer->zoom_factor = 1.0f;
viewer->offset_x = 0;
viewer->offset_y = 0;
viewer->dragging = 0;
viewer->image_width = 0;
viewer->image_height = 0;
return 1;
}
int load_image(ImageViewer* viewer, const char* filename) {
if (viewer->texture) {
SDL_DestroyTexture(viewer->texture);
viewer->texture = NULL;
}
SDL_Surface* surface = IMG_Load(filename);
if (!surface) {
printf("Unable to load image %s! SDL_image Error: %s\n", filename, IMG_GetError());
return 0;
}
viewer->texture = SDL_CreateTextureFromSurface(viewer->renderer, surface);
if (!viewer->texture) {
printf("Unable to create texture from %s! SDL_Error: %s\n", filename, SDL_GetError());
SDL_FreeSurface(surface);
return 0;
}
viewer->image_width = surface->w;
viewer->image_height = surface->h;
SDL_FreeSurface(surface);
strncpy(viewer->current_file, filename, MAX_PATH_LEN - 1);
viewer->current_file[MAX_PATH_LEN - 1] = '\0';
viewer->zoom_factor = 1.0f;
viewer->offset_x = 0;
viewer->offset_y = 0;
int window_w, window_h;
SDL_GetWindowSize(viewer->window, &window_w, &window_h);
float scale_x = (float)window_w / viewer->image_width;
float scale_y = (float)window_h / viewer->image_height;
float auto_scale = (scale_x < scale_y) ? scale_x : scale_y;
if (auto_scale < 1.0f) {
viewer->zoom_factor = auto_scale * 0.9f;
}
printf("Loaded image: %s (%dx%d)\n", filename, viewer->image_width, viewer->image_height);
return 1;
}
void render_image(ImageViewer* viewer) {
SDL_SetRenderDrawColor(viewer->renderer, 32, 32, 32, 255);
SDL_RenderClear(viewer->renderer);
if (!viewer->texture) {
SDL_RenderPresent(viewer->renderer);
return;
}
int scaled_width = (int)(viewer->image_width * viewer->zoom_factor);
int scaled_height = (int)(viewer->image_height * viewer->zoom_factor);
int window_w, window_h;
SDL_GetWindowSize(viewer->window, &window_w, &window_h);
int x = (window_w - scaled_width) / 2 + viewer->offset_x;
int y = (window_h - scaled_height) / 2 + viewer->offset_y;
SDL_Rect dest_rect = {x, y, scaled_width, scaled_height};
SDL_RenderCopy(viewer->renderer, viewer->texture, NULL, &dest_rect);
SDL_RenderPresent(viewer->renderer);
}
void handle_zoom(ImageViewer* viewer, float zoom_delta, int mouse_x, int mouse_y) {
float old_zoom = viewer->zoom_factor;
viewer->zoom_factor += zoom_delta;
if (viewer->zoom_factor < 0.1f) viewer->zoom_factor = 0.1f;
if (viewer->zoom_factor > 10.0f) viewer->zoom_factor = 10.0f;
float zoom_ratio = viewer->zoom_factor / old_zoom;
int window_w, window_h;
SDL_GetWindowSize(viewer->window, &window_w, &window_h);
int center_x = window_w / 2;
int center_y = window_h / 2;
viewer->offset_x = (viewer->offset_x - (mouse_x - center_x)) * zoom_ratio + (mouse_x - center_x);
viewer->offset_y = (viewer->offset_y - (mouse_y - center_y)) * zoom_ratio + (mouse_y - center_y);
}
void print_help() {
printf("\n=== JPG Image Viewer Controls ===\n");
printf("Mouse wheel / +/-: Zoom in/out\n");
printf("Mouse drag: Pan image\n");
printf("R: Reset zoom and position\n");
printf("F: Fit image to window\n");
printf("H: Show this help\n");
printf("ESC/Q: Quit\n");
printf("==================================\n\n");
}
void cleanup_viewer(ImageViewer* viewer) {
if (viewer->texture) {
SDL_DestroyTexture(viewer->texture);
}
if (viewer->renderer) {
SDL_DestroyRenderer(viewer->renderer);
}
if (viewer->window) {
SDL_DestroyWindow(viewer->window);
}
IMG_Quit();
SDL_Quit();
}
int main(int argc, char* argv[]) {
if (argc != 2) {
printf("Usage: %s <image_file.jpg>\n", argv[0]);
printf("Supported formats: JPG, JPEG, PNG, BMP, GIF, TIF\n");
return 1;
}
ImageViewer viewer;
if (!init_viewer(&viewer)) {
printf("Failed to initialize image viewer!\n");
return 1;
}
if (!load_image(&viewer, argv[1])) {
printf("Failed to load image: %s\n", argv[1]);
cleanup_viewer(&viewer);
return 1;
}
print_help();
int quit = 0;
SDL_Event e;
while (!quit) {
while (SDL_PollEvent(&e)) {
switch (e.type) {
case SDL_QUIT:
quit = 1;
break;
case SDL_KEYDOWN:
switch (e.key.keysym.sym) {
case SDLK_ESCAPE:
case SDLK_q:
quit = 1;
break;
case SDLK_r:
viewer.zoom_factor = 1.0f;
viewer.offset_x = 0;
viewer.offset_y = 0;
printf("Reset view\n");
break;
case SDLK_f:
{
int window_w, window_h;
SDL_GetWindowSize(viewer.window, &window_w, &window_h);
float scale_x = (float)window_w / viewer.image_width;
float scale_y = (float)window_h / viewer.image_height;
viewer.zoom_factor = ((scale_x < scale_y) ? scale_x : scale_y) * 0.9f;
viewer.offset_x = 0;
viewer.offset_y = 0;
printf("Fit to window (zoom: %.2f)\n", viewer.zoom_factor);
}
break;
case SDLK_PLUS:
case SDLK_EQUALS:
handle_zoom(&viewer, 0.1f, WINDOW_WIDTH/2, WINDOW_HEIGHT/2);
printf("Zoom: %.2f\n", viewer.zoom_factor);
break;
case SDLK_MINUS:
handle_zoom(&viewer, -0.1f, WINDOW_WIDTH/2, WINDOW_HEIGHT/2);
printf("Zoom: %.2f\n", viewer.zoom_factor);
break;
case SDLK_h:
print_help();
break;
}
break;
case SDL_MOUSEWHEEL:
{
int mouse_x, mouse_y;
SDL_GetMouseState(&mouse_x, &mouse_y);
float zoom_delta = e.wheel.y * 0.1f;
handle_zoom(&viewer, zoom_delta, mouse_x, mouse_y);
printf("Zoom: %.2f\n", viewer.zoom_factor);
}
break;
case SDL_MOUSEBUTTONDOWN:
if (e.button.button == SDL_BUTTON_LEFT) {
viewer.dragging = 1;
viewer.last_mouse_x = e.button.x;
viewer.last_mouse_y = e.button.y;
}
break;
case SDL_MOUSEBUTTONUP:
if (e.button.button == SDL_BUTTON_LEFT) {
viewer.dragging = 0;
}
break;
case SDL_MOUSEMOTION:
if (viewer.dragging) {
int dx = e.motion.x - viewer.last_mouse_x;
int dy = e.motion.y - viewer.last_mouse_y;
viewer.offset_x += dx;
viewer.offset_y += dy;
viewer.last_mouse_x = e.motion.x;
viewer.last_mouse_y = e.motion.y;
}
break;
case SDL_WINDOWEVENT:
if (e.window.event == SDL_WINDOWEVENT_RESIZED) {
printf("Window resized to %dx%d\n", e.window.data1, e.window.data2);
}
break;
}
}
render_image(&viewer);
SDL_Delay(16);
}
cleanup_viewer(&viewer);
printf("Image viewer closed.\n");
return 0;
}
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