nx_bmp.nx source

1// nx_bmp.nx -- sovereign 24-bit BMP writer, so detector output is VIEWABLE 2// directly on Windows (double-click) with no browser, no PNG encoder, no 3// third-party. BI_RGB, bottom-up, BGR, rows padded to 4 bytes. 4// 5// genealogy_id: microsoft_bmp_bi_rgb (record-hint) 6// lineage_id: bmp_fileheader + infoheader + bgr_bottom_up 7// license_tier: ORIGINAL 8import "syscalls.nx" 9import "nx_image.nx" 10 11func bmp_u32(fd: i64, v: i64) -> i64 { 12 let b: *u8 = sys_mmap(4) 13 b[0] = (v & 255) as u8 14 b[1] = ((v >> 8) & 255) as u8 15 b[2] = ((v >> 16) & 255) as u8 16 b[3] = ((v >> 24) & 255) as u8 17 sys_write(fd, b, 4) 18 return 0 19} 20func bmp_u16(fd: i64, v: i64) -> i64 { 21 let b: *u8 = sys_mmap(2) 22 b[0] = (v & 255) as u8 23 b[1] = ((v >> 8) & 255) as u8 24 sys_write(fd, b, 2) 25 return 0 26} 27 28// Write an RGB *Image as a 24-bit BMP. Returns 0 ok / -1 fail. 29func bmp_write(img: *Image, path: *u8) -> i64 { 30 let w: i64 = img.width 31 let h: i64 = img.height 32 let row3: i64 = w * 3 33 let pad: i64 = (4 - (row3 % 4)) % 4 34 let rowstride: i64 = row3 + pad 35 let datasize: i64 = rowstride * h 36 let filesize: i64 = 54 + datasize 37 38 let fd: i64 = sys_openat_wr(path, 420) 39 if fd < 0 { return 0 - 1 } 40 // BITMAPFILEHEADER (14 bytes) 41 sys_write(fd, "BM\x00" as *u8, 2) 42 bmp_u32(fd, filesize) 43 bmp_u32(fd, 0) 44 bmp_u32(fd, 54) 45 // BITMAPINFOHEADER (40 bytes) 46 bmp_u32(fd, 40) 47 bmp_u32(fd, w) 48 bmp_u32(fd, h) 49 bmp_u16(fd, 1) 50 bmp_u16(fd, 24) 51 bmp_u32(fd, 0) 52 bmp_u32(fd, datasize) 53 bmp_u32(fd, 0) 54 bmp_u32(fd, 0) 55 bmp_u32(fd, 0) 56 bmp_u32(fd, 0) 57 // pixels, bottom-up, BGR 58 let rowbuf: *u8 = sys_mmap(rowstride + 4) 59 var y: i64 = h - 1 60 while y >= 0 { 61 var x: i64 = 0 62 while x < w { 63 let r: i64 = nx_image_get(img, x, y, 0) 64 let g: i64 = nx_image_get(img, x, y, 1) 65 let b: i64 = nx_image_get(img, x, y, 2) 66 rowbuf[x * 3] = b as u8 67 rowbuf[x * 3 + 1] = g as u8 68 rowbuf[x * 3 + 2] = r as u8 69 x = x + 1 70 } 71 var p: i64 = 0 72 while p < pad { rowbuf[row3 + p] = 0 as u8; p = p + 1 } 73 sys_write(fd, rowbuf, rowstride) 74 y = y - 1 75 } 76 sys_close(fd) 77 return 0 78}