Bitmap pixelweise auslesen
-
Hallo zusammen,
wie kann ich ein itmap pixelweise auslesen. Ich will den farbwert jedes Pixels einzeln haben und in ein Array legen... .
Vielen Dank
Viele Grüße
Edwart
-
Such dir doch im Netz eine Doku über den Dateiaufbau von Bitmap-files und bau dein Prog dementsprechend auf. Der bmp-Dateiaufbau ist ziemlich simpel...
-
http://web.uccs.edu/wbahn/ECE1021/STATIC/REFERENCES/bmpfileformat.htm
http://astronomy.swin.edu.au/~pbourke/dataformats/bmp/
Damit hzab ich damals gearbeitet und hat wunderbar geklappt.
-
irgendwie schnall ich es nicht!
habt Ihr irgendwo ein kleines Beispiel wie ich an die Infos der Pixel auf der x/y-Koordinate komme?
Sinn ist es dies als Heightmap zu nutzen..
derzeit verwende ich ich txt-file, die aber stark begrenzt ist.
vielen dank
viele grüße
Edwart
-
Hilfe, könnte mir bitte jemand ein beispiel posten, wie man das macht?
Danke
Edwart
-
/* * Windows BMP file functions for OpenGL. * * Written by Michael Sweet. */ #include "bitmap.h" #include <stdio.h> #include <stdlib.h> #include <errno.h> #ifdef WIN32 /* * 'LoadDIBitmap()' - Load a DIB/BMP file from disk. * * Returns a pointer to the bitmap if successful, NULL otherwise... */ GLubyte * /* O - Bitmap data */ LoadDIBitmap(const char *filename, /* I - File to load */ BITMAPINFO **info) /* O - Bitmap information */ { FILE *fp; /* Open file pointer */ GLubyte *bits; /* Bitmap pixel bits */ int bitsize; /* Size of bitmap */ int infosize; /* Size of header information */ BITMAPFILEHEADER header; /* File header */ /* Try opening the file; use "rb" mode to read this *binary* file. */ if ((fp = fopen(filename, "rb")) == NULL) return (NULL); /* Read the file header and any following bitmap information... */ if (fread(&header, sizeof(BITMAPFILEHEADER), 1, fp) < 1) { /* Couldn't read the file header - return NULL... */ fclose(fp); return (NULL); } if (header.bfType != 'MB') /* Check for BM reversed... */ { /* Not a bitmap file - return NULL... */ fclose(fp); return (NULL); } infosize = header.bfOffBits - sizeof(BITMAPFILEHEADER); if ((*info = (BITMAPINFO *)malloc(infosize)) == NULL) { /* Couldn't allocate memory for bitmap info - return NULL... */ fclose(fp); return (NULL); } if (fread(*info, 1, infosize, fp) < infosize) { /* Couldn't read the bitmap header - return NULL... */ free(*info); fclose(fp); return (NULL); } /* Now that we have all the header info read in, allocate memory for * * the bitmap and read *it* in... */ if ((bitsize = (*info)->bmiHeader.biSizeImage) == 0) bitsize = ((*info)->bmiHeader.biWidth * (*info)->bmiHeader.biBitCount + 7) / 8 * abs((*info)->bmiHeader.biHeight); if ((bits = malloc(bitsize)) == NULL) { /* Couldn't allocate memory - return NULL! */ free(*info); fclose(fp); return (NULL); } if (fread(bits, 1, bitsize, fp) < bitsize) { /* Couldn't read bitmap - free memory and return NULL! */ free(*info); free(bits); fclose(fp); return (NULL); } /* OK, everything went fine - return the allocated bitmap... */ fclose(fp); return (bits); } /* * 'SaveDIBitmap()' - Save a DIB/BMP file to disk. * * Returns 0 on success or -1 on failure... */ int /* O - 0 = success, -1 = failure */ SaveDIBitmap(const char *filename, /* I - File to load */ BITMAPINFO *info, /* I - Bitmap information */ GLubyte *bits) /* I - Bitmap data */ { FILE *fp; /* Open file pointer */ int size, /* Size of file */ infosize, /* Size of bitmap info */ bitsize; /* Size of bitmap pixels */ BITMAPFILEHEADER header; /* File header */ /* Try opening the file; use "wb" mode to write this *binary* file. */ if ((fp = fopen(filename, "wb")) == NULL) return (-1); /* Figure out the bitmap size */ if (info->bmiHeader.biSizeImage == 0) bitsize = (info->bmiHeader.biWidth * info->bmiHeader.biBitCount + 7) / 8 * abs(info->bmiHeader.biHeight); else bitsize = info->bmiHeader.biSizeImage; /* Figure out the header size */ infosize = sizeof(BITMAPINFOHEADER); switch (info->bmiHeader.biCompression) { case BI_BITFIELDS : infosize += 12; /* Add 3 RGB doubleword masks */ if (info->bmiHeader.biClrUsed == 0) break; case BI_RGB : if (info->bmiHeader.biBitCount > 8 && info->bmiHeader.biClrUsed == 0) break; case BI_RLE8 : case BI_RLE4 : if (info->bmiHeader.biClrUsed == 0) infosize += (1 << info->bmiHeader.biBitCount) * 4; else infosize += info->bmiHeader.biClrUsed * 4; break; } size = sizeof(BITMAPFILEHEADER) + infosize + bitsize; /* Write the file header, bitmap information, and bitmap pixel data... */ header.bfType = 'MB'; /* Non-portable... sigh */ header.bfSize = size; header.bfReserved1 = 0; header.bfReserved2 = 0; header.bfOffBits = sizeof(BITMAPFILEHEADER) + infosize; if (fwrite(&header, 1, sizeof(BITMAPFILEHEADER), fp) < sizeof(BITMAPFILEHEADER)) { /* Couldn't write the file header - return... */ fclose(fp); return (-1); } if (fwrite(info, 1, infosize, fp) < infosize) { /* Couldn't write the bitmap header - return... */ fclose(fp); return (-1); } if (fwrite(bits, 1, bitsize, fp) < bitsize) { /* Couldn't write the bitmap - return... */ fclose(fp); return (-1); } /* OK, everything went fine - return... */ fclose(fp); return (0); } #else /* !WIN32 */ /* * Functions for reading and writing 16- and 32-bit little-endian integers. */ static unsigned short read_word(FILE *fp); static unsigned int read_dword(FILE *fp); static int read_long(FILE *fp); static int write_word(FILE *fp, unsigned short w); static int write_dword(FILE *fp, unsigned int dw); static int write_long(FILE *fp, int l); /* * 'LoadDIBitmap()' - Load a DIB/BMP file from disk. * * Returns a pointer to the bitmap if successful, NULL otherwise... */ GLubyte * /* O - Bitmap data */ LoadDIBitmap(const char *filename, /* I - File to load */ BITMAPINFO **info) /* O - Bitmap information */ { FILE *fp; /* Open file pointer */ GLubyte *bits; /* Bitmap pixel bits */ GLubyte *ptr; /* Pointer into bitmap */ GLubyte temp; /* Temporary variable to swap red and blue */ int x, y; /* X and Y position in image */ int length; /* Line length */ int bitsize; /* Size of bitmap */ int infosize; /* Size of header information */ BITMAPFILEHEADER header; /* File header */ /* Try opening the file; use "rb" mode to read this *binary* file. */ if ((fp = fopen(filename, "rb")) == NULL) return (NULL); /* Read the file header and any following bitmap information... */ header.bfType = read_word(fp); header.bfSize = read_dword(fp); header.bfReserved1 = read_word(fp); header.bfReserved2 = read_word(fp); header.bfOffBits = read_dword(fp); if (header.bfType != BF_TYPE) /* Check for BM reversed... */ { /* Not a bitmap file - return NULL... */ fclose(fp); return (NULL); } infosize = header.bfOffBits - 18; if ((*info = (BITMAPINFO *)malloc(sizeof(BITMAPINFO))) == NULL) { /* Couldn't allocate memory for bitmap info - return NULL... */ fclose(fp); return (NULL); } (*info)->bmiHeader.biSize = read_dword(fp); (*info)->bmiHeader.biWidth = read_long(fp); (*info)->bmiHeader.biHeight = read_long(fp); (*info)->bmiHeader.biPlanes = read_word(fp); (*info)->bmiHeader.biBitCount = read_word(fp); (*info)->bmiHeader.biCompression = read_dword(fp); (*info)->bmiHeader.biSizeImage = read_dword(fp); (*info)->bmiHeader.biXPelsPerMeter = read_long(fp); (*info)->bmiHeader.biYPelsPerMeter = read_long(fp); (*info)->bmiHeader.biClrUsed = read_dword(fp); (*info)->bmiHeader.biClrImportant = read_dword(fp); if (infosize > 40) if (fread((*info)->bmiColors, infosize - 40, 1, fp) < 1) { /* Couldn't read the bitmap header - return NULL... */ free(*info); fclose(fp); return (NULL); } /* Now that we have all the header info read in, allocate memory for * * the bitmap and read *it* in... */ if ((bitsize = (*info)->bmiHeader.biSizeImage) == 0) bitsize = ((*info)->bmiHeader.biWidth * (*info)->bmiHeader.biBitCount + 7) / 8 * abs((*info)->bmiHeader.biHeight); if ((bits = malloc(bitsize)) == NULL) { /* Couldn't allocate memory - return NULL! */ free(*info); fclose(fp); return (NULL); } if (fread(bits, 1, bitsize, fp) < bitsize) { /* Couldn't read bitmap - free memory and return NULL! */ free(*info); free(bits); fclose(fp); return (NULL); } /* Swap red and blue */ length = ((*info)->bmiHeader.biWidth * 3 + 3) & ~3; for (y = 0; y < (*info)->bmiHeader.biHeight; y ++) for (ptr = bits + y * length, x = (*info)->bmiHeader.biWidth; x > 0; x --, ptr += 3) { temp = ptr[0]; ptr[0] = ptr[2]; ptr[2] = temp; } /* OK, everything went fine - return the allocated bitmap... */ fclose(fp); return (bits); } /* * 'SaveDIBitmap()' - Save a DIB/BMP file to disk. * * Returns 0 on success or -1 on failure... */ int /* O - 0 = success, -1 = failure */ SaveDIBitmap(const char *filename, /* I - File to load */ BITMAPINFO *info, /* I - Bitmap information */ GLubyte *bits) /* I - Bitmap data */ { FILE *fp; /* Open file pointer */ int size, /* Size of file */ infosize, /* Size of bitmap info */ bitsize; /* Size of bitmap pixels */ /* Try opening the file; use "wb" mode to write this *binary* file. */ if ((fp = fopen(filename, "wb")) == NULL) return (-1); /* Figure out the bitmap size */ if (info->bmiHeader.biSizeImage == 0) bitsize = (info->bmiHeader.biWidth * info->bmiHeader.biBitCount + 7) / 8 * abs(info->bmiHeader.biHeight); else bitsize = info->bmiHeader.biSizeImage; /* Figure out the header size */ infosize = sizeof(BITMAPINFOHEADER); switch (info->bmiHeader.biCompression) { case BI_BITFIELDS : infosize += 12; /* Add 3 RGB doubleword masks */ if (info->bmiHeader.biClrUsed == 0) break; case BI_RGB : if (info->bmiHeader.biBitCount > 8 && info->bmiHeader.biClrUsed == 0) break; case BI_RLE8 : case BI_RLE4 : if (info->bmiHeader.biClrUsed == 0) infosize += (1 << info->bmiHeader.biBitCount) * 4; else infosize += info->bmiHeader.biClrUsed * 4; break; } size = sizeof(BITMAPFILEHEADER) + infosize + bitsize; /* Write the file header, bitmap information, and bitmap pixel data... */ write_word(fp, BF_TYPE); /* bfType */ write_dword(fp, size); /* bfSize */ write_word(fp, 0); /* bfReserved1 */ write_word(fp, 0); /* bfReserved2 */ write_dword(fp, 18 + infosize); /* bfOffBits */ write_dword(fp, info->bmiHeader.biSize); write_long(fp, info->bmiHeader.biWidth); write_long(fp, info->bmiHeader.biHeight); write_word(fp, info->bmiHeader.biPlanes); write_word(fp, info->bmiHeader.biBitCount); write_dword(fp, info->bmiHeader.biCompression); write_dword(fp, info->bmiHeader.biSizeImage); write_long(fp, info->bmiHeader.biXPelsPerMeter); write_long(fp, info->bmiHeader.biYPelsPerMeter); write_dword(fp, info->bmiHeader.biClrUsed); write_dword(fp, info->bmiHeader.biClrImportant); if (infosize > 40) if (fwrite(info->bmiColors, infosize - 40, 1, fp) < 1) { /* Couldn't write the bitmap header - return... */ fclose(fp); return (-1); } if (fwrite(bits, 1, bitsize, fp) < bitsize) { /* Couldn't write the bitmap - return... */ fclose(fp); return (-1); } /* OK, everything went fine - return... */ fclose(fp); return (0); } /* * 'read_word()' - Read a 16-bit unsigned integer. */ static unsigned short /* O - 16-bit unsigned integer */ read_word(FILE *fp) /* I - File to read from */ { unsigned char b0, b1; /* Bytes from file */ b0 = getc(fp); b1 = getc(fp); return ((b1 << 8) | b0); } /* * 'read_dword()' - Read a 32-bit unsigned integer. */ static unsigned int /* O - 32-bit unsigned integer */ read_dword(FILE *fp) /* I - File to read from */ { unsigned char b0, b1, b2, b3; /* Bytes from file */ b0 = getc(fp); b1 = getc(fp); b2 = getc(fp); b3 = getc(fp); return ((((((b3 << 8) | b2) << 8) | b1) << 8) | b0); } /* * 'read_long()' - Read a 32-bit signed integer. */ static int /* O - 32-bit signed integer */ read_long(FILE *fp) /* I - File to read from */ { unsigned char b0, b1, b2, b3; /* Bytes from file */ b0 = getc(fp); b1 = getc(fp); b2 = getc(fp); b3 = getc(fp); return ((int)(((((b3 << 8) | b2) << 8) | b1) << 8) | b0); } /* * 'write_word()' - Write a 16-bit unsigned integer. */ static int /* O - 0 on success, -1 on error */ write_word(FILE *fp, /* I - File to write to */ unsigned short w) /* I - Integer to write */ { putc(w, fp); return (putc(w >> 8, fp)); } /* * 'write_dword()' - Write a 32-bit unsigned integer. */ static int /* O - 0 on success, -1 on error */ write_dword(FILE *fp, /* I - File to write to */ unsigned int dw) /* I - Integer to write */ { putc(dw, fp); putc(dw >> 8, fp); putc(dw >> 16, fp); return (putc(dw >> 24, fp)); } /* * 'write_long()' - Write a 32-bit signed integer. */ static int /* O - 0 on success, -1 on error */ write_long(FILE *fp, /* I - File to write to */ int l) /* I - Integer to write */ { putc(l, fp); putc(l >> 8, fp); putc(l >> 16, fp); return (putc(l >> 24, fp)); } #endif /* WIN32 */
-
Kann alternativ noch nen Beispiel in C beisteuern, bei intresse schreib mir ne PN
-
eieiei, was ein Tag. es klappt ja gar nichts bei mir...
wo ist denn nun der Knopf für PNs?
THE_FreaK -> ja bitte posten ;-).. finde den Button für PNs nicht.
-
Edwart schrieb:
wo ist denn nun der Knopf für PNs?
Äh, es gibt hier keine
-
sabalot, ich krieg es einfach nicht hin, die Farbdaten auszulesen.
so ein schmodder -
hilfe
