diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 3bbfc37..9a1cc8b 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -1,3 +1,4 @@
 add_executable(ddl_ar ddl_ar.cpp ddl_ar_class.cpp)
+add_executable(pcx_diff_tool pcx_diff_tool.c)
 
 set_property(TARGET ddl_ar PROPERTY CXX_STANDARD 20)
diff --git a/tools/pcx_diff_tool.c b/tools/pcx_diff_tool.c
new file mode 100644
index 0000000..a9562e3
--- /dev/null
+++ b/tools/pcx_diff_tool.c
@@ -0,0 +1,176 @@
+// pcx_diff_tool.c
+// Jednoduchý nástroj pro porovnání dvou PCX souborů (8-bit) a uložení rozdílu do nového PCX
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#define PCX_HEADER_SIZE 128
+#define PALETTE_SIZE 768
+
+typedef struct {
+    uint8_t *data;
+    int width, height;
+    uint8_t palette[PALETTE_SIZE];
+} PCXImage;
+
+// ------------------------ PCX Dekodovani ------------------------
+
+int pcx_decode_rle(FILE *f, uint8_t *out, int size) {
+    int count = 0;
+    while (count < size) {
+        int byte = fgetc(f);
+        if (byte == EOF) return -1;
+
+        if ((byte & 0xC0) == 0xC0) {
+            int reps = byte & 0x3F;
+            int val = fgetc(f);
+            if (val == EOF) return -1;
+            for (int i = 0; i < reps && count < size; ++i) out[count++] = val;
+        } else {
+            out[count++] = byte;
+        }
+    }
+    return 0;
+}
+
+PCXImage *pcx_load(const char *filename) {
+    FILE *f = fopen(filename, "rb");
+    if (!f) return NULL;
+
+    uint8_t header[PCX_HEADER_SIZE];
+    fread(header, 1, PCX_HEADER_SIZE, f);
+
+    if (header[0] != 0x0A || header[3] != 8 || header[65] != 1) {
+        fclose(f);
+        return NULL; // Neplatný formát
+    }
+
+    int x1 = header[4] | (header[5] << 8);
+    int y1 = header[6] | (header[7] << 8);
+    int x2 = header[8] | (header[9] << 8);
+    int y2 = header[10] | (header[11] << 8);
+
+    int width = x2 - x1 + 1;
+    int height = y2 - y1 + 1;
+
+    PCXImage *img = calloc(1, sizeof(PCXImage));
+    img->width = width;
+    img->height = height;
+    img->data = malloc(width * height);
+
+    pcx_decode_rle(f, img->data, width * height);
+
+    fseek(f, -PALETTE_SIZE - 1, SEEK_END); // -1 pro 0x0C
+    int palette_marker = fgetc(f);
+    if (palette_marker != 0x0C) {
+        fclose(f);
+        free(img->data);
+        free(img);
+        return NULL; // Paleta není přítomna
+    }
+    fread(img->palette, 1, PALETTE_SIZE, f);
+
+    fclose(f);
+    return img;
+}
+
+void pcx_free(PCXImage *img) {
+    if (!img) return;
+    free(img->data);
+    free(img);
+}
+
+// ------------------------ PCX Ulozeni ------------------------
+
+void pcx_write_rle(FILE *f, uint8_t *data, int size, int width) {
+    int w = width;
+    for (int i = 0; i < size;) {
+        uint8_t val = data[i];
+        int count = 1;
+        while (count < 63 && count < w && i + count < size && data[i + count] == val) count++;
+        if (count > 1 || (val & 0xC0) == 0xC0) {
+            fputc(0xC0 | count, f);
+            fputc(val, f);
+        } else {
+            fputc(val, f);
+        }
+        w -= count;
+        i += count;
+        if (w == 0) {
+            w = width;
+        }
+    }
+}
+
+int pcx_save(const char *filename, PCXImage *img) {
+    FILE *f = fopen(filename, "wb");
+    if (!f) return -1;
+
+    uint8_t header[PCX_HEADER_SIZE] = {0};
+    header[0] = 0x0A; // manufacturer
+    header[1] = 5;    // version
+    header[2] = 1;    // encoding
+    header[3] = 8;    // bits per pixel
+    header[4] = 0; header[5] = 0; // xmin
+    header[6] = 0; header[7] = 0; // ymin
+    header[8] = (img->width - 1) & 0xFF;
+    header[9] = (img->width - 1) >> 8;
+    header[10] = (img->height - 1) & 0xFF;
+    header[11] = (img->height - 1) >> 8;
+    header[12] = 72; header[13] = 0; // hres (72 dpi)
+    header[14] = 72; header[15] = 0; // vres (72 dpi)
+    header[65] = 1; // planes
+    header[66] = img->width & 0xFF;
+    header[67] = img->width >> 8; // bytes per line
+    header[68] = 1; header[69] = 0; // palette type (1 = color)
+
+    fwrite(header, 1, PCX_HEADER_SIZE, f);
+    pcx_write_rle(f, img->data, img->width * img->height, img->width);
+
+    fputc(0x0C, f); // Palette ID
+    fwrite(img->palette, 1, PALETTE_SIZE, f);
+
+    fclose(f);
+    return 0;
+}
+
+// ------------------------ Hlavní funkce ------------------------
+
+int main(int argc, char **argv) {
+    if (argc != 4) {
+        printf("Použití: %s <referencni.pcx> <komprimovany.pcx> <vystup.pcx>\n", argv[0]);
+        return 1;
+    }
+
+    PCXImage *ref = pcx_load(argv[1]);
+    PCXImage *src = pcx_load(argv[2]);
+
+    if (!ref || !src) {
+        printf("Chyba při čtení PCX souborů\n");
+        return 1;
+    }
+
+    if (ref->width != src->width || ref->height != src->height) {
+        printf("Rozměry nesouhlasí!\n");
+        return 1;
+    }
+
+    PCXImage out = {0};
+    out.width = ref->width;
+    out.height = ref->height;
+    out.data = malloc(out.width * out.height);
+    memcpy(out.palette, src->palette, PALETTE_SIZE);
+
+    for (int i = 0; i < out.width * out.height; i++) {
+        out.data[i] = src->data[i] ^ ref->data[i];
+    }
+
+    pcx_save(argv[3], &out);
+
+    pcx_free(ref);
+    pcx_free(src);
+    free(out.data);
+    return 0;
+}