2018-11-12 13:25:24 +00:00
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/**
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* \file common.c
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* \brief Implémentation de la (dé)compression d’images
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*/
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2018-11-06 15:08:20 +00:00
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#include "common.h"
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2018-11-12 13:25:24 +00:00
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/**
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* Cette fonction permet d’évaluer si le pixel passé en argument est éligible à
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* la zone passée également en argument.
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*
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* \param[in] t_pixel Pointeur vers le pixel dont l’éligibilité est testée
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* \param[in] t_zone Zone à laquelle le pixel est éligible ou non
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* \return Valeur booléenne, `true` si le pixel est éligible, `false` sinon
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*/
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2018-11-06 15:08:20 +00:00
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bool sameColor(Pixel_t t_pixel, Zone_t t_zone) {
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return t_pixel->r == t_zone->r && t_pixel->g == t_zone->g &&
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t_pixel->b == t_zone->b;
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}
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2018-11-12 13:25:24 +00:00
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/**
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* Ajoute un pixel à la zone passé en argument si le pixel à l’index passé en
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* argument est éligible à la zone. Si un pixel n’a pas encore été visité, cela
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* veut dire également qu’il ne fait partie d’aucun segment, il sera donc
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* ajouté à un nouveau segment auquel seront rajoutés tous les pixels connexes
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* éligibles à la zone. Ensuite, le segment est ajouté à la zone, et la
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* fonction actuelle est appelée sur tous les pixels supérieurs et inférieurs
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* aux pixels du segment.
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*
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* \param[in] t_img Image contenant les pixels explorés
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* \param[in] t_idx Index du pixel actuel dans l’image `t_img`
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* \param[out] t_zone Zone à laquelle sera potentiellement ajouté le pixel
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*/
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2018-11-06 15:08:20 +00:00
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void addPixelToSelectedZone(Image_t t_img, int t_idx, Zone_t t_zone) {
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Pixel_t current_pixel;
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2018-11-07 00:03:55 +00:00
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int xd, xg, y = t_idx / (int)t_img->x;
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2018-11-06 15:08:20 +00:00
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current_pixel = darrayGet(t_img->pixels, t_idx);
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if (current_pixel->visited || t_idx >= (int)darraySize(t_img->pixels) ||
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t_idx < 0 || !sameColor(current_pixel, t_zone)) {
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return;
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}
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(*current_pixel).visited = true;
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for(xd = t_idx; xd % (int)t_img->x != 0; ++xd) { /* fetch right limit of segment */
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current_pixel = darrayGet(t_img->pixels, xd);
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if(!sameColor(current_pixel, t_zone)) {
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break;
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}
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(*current_pixel).visited = true;
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}
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2018-11-07 00:03:55 +00:00
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for(xg = t_idx; xg - y >= 0; --xg) { /* fetch right limit of segment */
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2018-11-06 15:08:20 +00:00
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current_pixel = darrayGet(t_img->pixels, xd);
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if(!sameColor(current_pixel, t_zone)) {
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break;
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}
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(*current_pixel).visited = true;
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}
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/* Add segment to its zone */
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2018-11-07 00:03:55 +00:00
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darrayPushBack(t_zone->segments, newSegment(y, xd, xg));
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2018-11-06 15:08:20 +00:00
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for(; xg <= xd; ++xg) { /* process every pixel up and down the segment */
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addPixelToSelectedZone(t_img, t_idx + t_img->x, t_zone);
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}
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}
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/* Selects the zone related to the pixel, skip tests if pixel has
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already been visited */
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void chooseZoneForPixel(Image_t t_img, int t_idx, darray_t zones) {
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Zone_t current_zone;
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Pixel_t pixel;
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size_t i;
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pixel = darrayGet(t_img->pixels, t_idx);
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if (pixel->visited)
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return;
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for (i = 0; i < darraySize(zones); ++i) {
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current_zone = darrayGet(zones, i);
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if (sameColor(pixel, current_zone)) {
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addPixelToSelectedZone(t_img, t_idx, current_zone);
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break;
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}
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}
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}
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/* converts an image to zones */
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darray_t imgToZones(Image_t t_img) {
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darray_t zones;
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const size_t nb_pixels = darraySize(t_img->pixels);
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size_t i;
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zones = darrayNew(sizeof(Zone));
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for (i = 0; i < nb_pixels; ++i) {
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chooseZoneForPixel(t_img, i, zones);
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}
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return zones;
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}
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2018-11-07 00:03:55 +00:00
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2018-11-11 15:32:27 +00:00
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void compress(const char *input_file) {
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2018-11-07 00:03:55 +00:00
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Image_t img;
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darray_t zones;
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img = newImage();
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imageLoadPPM(input_file, img);
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zones = imgToZones(img);
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darrayDelete(zones);
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2018-11-11 15:32:27 +00:00
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printf("Detected %zu zones\n", darraySize(zones));
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2018-11-07 00:03:55 +00:00
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deleteImage(img);
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}
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