/meta/ – Diskussionen über Dietchan

exiftool EC/Cockopter_downsize.jpg
ExifTool Version Number         : 13.36
File Name                       : Cockopter_downsize.jpg
Directory                       : EC
File Size                       : 9.9 MB
File Modification Date/Time     : 2024:08:01 11:39:57+02:00
File Access Date/Time           : 2025:11:23 11:20:38+01:00
File Inode Change Date/Time     : 2024:08:01 11:39:57+02:00
File Permissions                : -rwxr-xr-x
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.01
Resolution Unit                 : cm
X Resolution                    : 236
Y Resolution                    : 236
Image Width                     : 22102
Image Height                    : 15480
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:4:4 (1 1)
Image Size                      : 22102x15480
Megapixels                      : 342.1

Nov 23 12:46:20 [...] Started job 120520 (file --mime-type --brief -k -r ./www/uploads/.tmpXXXXXXXXXX || file --mime-type --brief ./www/uploads/.tmpXXXXXXXXXX)
Nov 23 12:46:20 [...] Exited job 120520
Nov 23 12:46:20 [...] Started job 120522 ( identify -format 'width=%w\nheight=%h\n' ./www/uploads/.tmpXXXXXXXXXX)
Nov 23 12:46:20 [...] Finalized job 120520
Nov 23 12:46:21 [...] identify: unable to write pixel cache '/tmp/magick-DWzu3lRFYVtw4o1vt6wPt5rxJhhrrDd3': No space left on device @ error/cache.c/WritePixelCachePixels/5984.
Nov 23 12:46:21 [...] identify: Application transferred too few scanlines `./www/uploads/.tmpXXXXXXXXXX' @ warning/jpeg.c/JPEGErrorHandler/353.
Nov 23 12:46:21 [...] Exited job 120522
Nov 23 12:46:21 [...] Finalized job 120522
Nov 23 12:47:31 [...] Started job 120534 (file --mime-type --brief -k -r ./www/uploads/.tmpYYYYYYYYYY || file --mime-type --brief ./www/uploads/.tmpYYYYYYYYYY)
Nov 23 12:47:31 [...] Exited job 120534
Nov 23 12:47:31 [...] Started job 120536 ( identify -format 'width=%w\nheight=%h\n' ./www/uploads/.tmpYYYYYYYYYY)
Nov 23 12:47:31 [...] Finalized job 120534
Nov 23 12:47:32 [...] identify: unable to write pixel cache '/tmp/magick-xmgFrqR6m5uVDpaEgDvA2oBkMw9sjfBo': No space left on device @ error/cache.c/WritePixelCachePixels/5984.
Nov 23 12:47:32 [...] identify: Application transferred too few scanlines `./www/uploads/.tmpYYYYYYYYYY' @ warning/jpeg.c/JPEGErrorHandler/353.

[Unit]
Description=Dietchan

[Service]
ExecStart=/blabla/dietchan -l blubb
OOMPolicy=continue

#include <stdio.h>
#include <stdint.h>
#include <string.h>

void identify_png(FILE *f) {
    uint8_t header[8];
    fread(header, 1, 8, f);
    if (memcmp(header, "\x89PNG\r\n\x1a\n", 8)) {
        printf("Not a PNG\n");
        return;
    }
    fseek(f, 8, SEEK_SET); // skip signature

    uint8_t chunk[25]; // IHDR is 25 bytes including length/type/CRC
    fread(chunk, 1, 25, f);
    if (memcmp(chunk+4, "IHDR", 4)) {
        printf("No IHDR chunk\n");
        return;
    }

    uint32_t width = (chunk[8]<<24)|(chunk[9]<<16)|(chunk[10]<<8)|chunk[11];
    uint32_t height = (chunk[12]<<24)|(chunk[13]<<16)|(chunk[14]<<8)|chunk[15];
    uint8_t bit_depth = chunk[16];
    uint8_t color_type = chunk[17];

    printf("PNG %ux%u %u-bit color_type %u\n", width, height, bit_depth, color_type);
}

void identify_jpeg(FILE *f) {
    uint8_t buf[2];
    fread(buf, 1, 2, f);
    if (buf[0] != 0xFF || buf[1] != 0xD8) {
        printf("Not a JPEG\n");
        return;
    }

    while (1) {
        if (fread(buf, 1, 2, f) != 2) break;
        if (buf[0] != 0xFF) continue;
        uint8_t marker = buf[1];

        if (marker >= 0xC0 && marker <= 0xC3) { // SOF markers
            fseek(f, 3, SEEK_CUR);
            uint8_t dim[4];
            fread(dim, 1, 4, f);
            uint16_t height = (dim[0]<<8)|dim[1];
            uint16_t width  = (dim[2]<<8)|dim[3];
            printf("JPEG %ux%u\n", width, height);
            return;
        } else {
            uint8_t size_buf[2];
            fread(size_buf,1,2,f);
            uint16_t size = (size_buf[0]<<8)|size_buf[1];
            fseek(f, size-2, SEEK_CUR);
        }
    }
    printf("JPEG dimensions not found\n");
}

int main(int argc, char **argv) {
    if (argc < 2) {
        printf("Usage: %s <image>\n", argv[0]);
        return 1;
    }

    FILE *f = fopen(argv[1], "rb");
    if (!f) { perror("fopen"); return 1; }

    uint8_t sig[8];
    fread(sig, 1, 8, f);
    fseek(f, 0, SEEK_SET);

    if (!memcmp(sig, "\x89PNG\r\n\x1a\n", 8))
        identify_png(f);
    else if (sig[0]==0xFF && sig[1]==0xD8)
        identify_jpeg(f);
    else
        printf("Unsupported format\n");

    fclose(f);
    return 0;
}

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <sys/stat.h>

typedef struct { uint32_t w,h; uint8_t depth; int channels; char format[16]; } ImgMeta;

// --- PNG ---
int identify_png(FILE *f, ImgMeta *meta){
    uint8_t buf[25];
    fseek(f,8,SEEK_SET);
    fread(buf,1,25,f);
    if(memcmp(buf+4,"IHDR",4)) return 0;
    meta->w = (buf[8]<<24)|(buf[9]<<16)|(buf[10]<<8)|buf[11];
    meta->h = (buf[12]<<24)|(buf[13]<<16)|(buf[14]<<8)|buf[15];
    meta->depth = buf[16];
    switch(buf[17]){
        case 0: meta->channels=1; break; // grayscale
        case 2: meta->channels=3; break; // RGB
        case 3: meta->channels=1; break; // palette
        case 4: meta->channels=2; break; // grayscale+alpha
        case 6: meta->channels=4; break; // RGBA
        default: meta->channels=3;
    }
    strcpy(meta->format,"PNG");
    return 1;
}

// --- JPEG ---
int identify_jpeg(FILE *f, ImgMeta *meta){
    uint8_t buf[2];
    fseek(f,0,SEEK_SET);
    fread(buf,1,2,f);
    if(buf[0]!=0xFF || buf[1]!=0xD8) return 0;
    while(1){
        if(fread(buf,1,2,f)!=2) break;
        if(buf[0]!=0xFF) continue;
        uint8_t marker = buf[1];
        if(marker>=0xC0 && marker<=0xC3){
            fseek(f,3,SEEK_CUR);
            uint8_t dim[4];
            fread(dim,1,4,f);
            meta->h=(dim[0]<<8)|dim[1];
            meta->w=(dim[2]<<8)|dim[3];
            meta->depth=8;
            meta->channels=3;
            strcpy(meta->format,"JPEG");
            return 1;
        } else {
            uint8_t sz[2];
            fread(sz,1,2,f);
            uint16_t size=(sz[0]<<8)|sz[1];
            fseek(f,size-2,SEEK_CUR);
        }
    }
    return 0;
}

// --- BMP ---
int identify_bmp(FILE *f, ImgMeta *meta){
    uint8_t hdr[26];
    fseek(f,0,SEEK_SET);
    fread(hdr,1,26,f);
    if(hdr[0]!='B'||hdr[1]!='M') return 0;
    meta->w = hdr[18]|(hdr[19]<<8)|(hdr[20]<<16)|(hdr[21]<<24);
    meta->h = hdr[22]|(hdr[23]<<8)|(hdr[24]<<16)|(hdr[25]<<24);
    meta->depth = 24;
    meta->channels = 3;
    strcpy(meta->format,"BMP");
    return 1;
}

// --- GIF ---
int identify_gif(FILE *f, ImgMeta *meta){
    uint8_t hdr[10];
    fseek(f,0,SEEK_SET);
    fread(hdr,1,10,f);
    if(memcmp(hdr,"GIF89a",6)&&memcmp(hdr,"GIF87a",6)) return 0;
    meta->w = hdr[6]|(hdr[7]<<8);
    meta->h = hdr[8]|(hdr[9]<<8);
    meta->depth = 8;
    meta->channels = 3;
    strcpy(meta->format,"GIF");
    return 1;
}

// --- WebP ---
int identify_webp(FILE *f, ImgMeta *meta){
    uint8_t hdr[12];
    fseek(f,0,SEEK_SET);
    fread(hdr,1,12,f);
    if(memcmp(hdr,"RIFF",4)||memcmp(hdr+8,"WEBP",4)) return 0;
    uint8_t fmt[4];
    fread(fmt,1,4,f);
    if(!memcmp(fmt,"VP8 ",4)){
        fseek(f,10,SEEK_CUR);
        uint8_t dim[4];
        fread(dim,1,4,f);
        meta->w=((dim[1]&0x3F)<<8)|dim[0];
        meta->h=((dim[3]&0x3F)<<8)|dim[2];
        meta->depth=24;
        meta->channels=3;
        strcpy(meta->format,"WebP");
        return 1;
    }
    return 0;
}

// --- Main ---
int main(int argc,char **argv){
    if(argc<2){ printf("Usage: %s <file>\n",argv[0]); return 1; }
    FILE *f=fopen(argv[1],"rb");
    if(!f){ perror("fopen"); return 1; }

    ImgMeta meta={0};
    int ok= identify_png(f,&meta)||
            identify_jpeg(f,&meta)||
            identify_bmp(f,&meta)||
            identify_gif(f,&meta)||
            identify_webp(f,&meta);

    fclose(f);

    if(ok){
        struct stat st;
        stat(argv[1], &st);
        double mib = st.st_size / 1024.0 / 1024.0;
        // Ident-like output
        printf("%s %s %ux%u %ux%u+0+0 %d-bit sRGB %.5fMiB 0.000u 0:00.000\n",
            argv[1], meta.format,
            meta.w, meta.h,
            meta.w, meta.h,
            meta.depth,
            mib
        );
    } else {
        printf("Unsupported format\n");
    }

    return 0;
}