TODO. open file update outfile s header info read infile s scanline, pixel by pixel resize horizontally remember padding!

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Esmond Price
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2 TODO open file update outfile s header info read infile s scanline, pixel by pixel resize horizontally remember padding! resize vertically

3 copy.c opens a file updates header info for outfile reads each scanline, pixel by pixel writes each pixel into the output file s scanline cp copy.c resize.c

4 TODO þ open file update outfile s header info read infile s scanline, pixel by pixel resize horizontally remember padding! resize vertically

5 bitmaps just an arrangement of bytes! how do we interpret this arrangement? bmp.h

6 updating header info new bmp à new header info what s changing? file size image size width height

7 BITMAPINFOHEADER biwidth width of image (in pixels) n does not include padding biheight height of image (in pixels)

8 BITMAPINFOHEADER bisizeimage total size of image (in bytes) n includes pixels and padding bi.bisizeimage = ((sizeof(rgbtriple) * bi.biwidth) + padding) * abs(bi.biheight);

9 BITMAPFILEHEADER bfsize total size of file (in bytes) includes pixels, padding, and headers bf.bfsize = bi.bisizeimage + sizeof(bitmapfileheader) + sizeof(bitmapinfoheader);

10 what s changing? old bi.biwidth bi.biheight bi.bisizeimage bf.bfsize new bi.biwidth *= n bi.biheight *= n...?...?

11 TODO þ open file þ update outfile s header info read infile s scanline, pixel by pixel resize horizontally remember padding! resize vertically

12 reading files fread(data, size, number, inptr); data: pointer to a struct that will contain the bytes you re reading size: size of each element to read sizeof number: number of elements to read inptr: FILE * to read from

13 TODO þ open file þ update outfile s header info þ read infile s scanline, pixel by pixel resize horizontally remember padding! resize vertically

14 resize horizontally n = 2 for each pixel in row write n times

15 resize horizontally n = 2 for each pixel in row write n times

16 resize horizontally n = 2 for each pixel in row write n times

17 resize horizontally n = 2 for each pixel in row write n times

18 writing files fwrite(data, size, number, outptr); data: pointer to the struct that contains the bytes you re reading from size number outptr: FILE * to write to

19 TODO þ open file þ update outfile s header s info þ read infile s scanline, pixel by pixel þ resize horizontally remember padding! resize vertically

20 padding each pixel is 3 bytes length of each scanline must be a multiple of 4 bytes if the number of pixels isn t a multiple of 4, we need padding padding is just zeros (0x00)

21 padding RGBtriple RGBtriple RGBtriple RGBtriple

22 padding RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple 0x00

23 padding RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple 0x00 RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple 0x00 0x00

24 padding RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple 0x00 RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple RGBtriple 0x00 0x00 RGBtriple RGBtriple RGBtriple 0x00 0x00 0x00

25 padding padding = (4 (bi.biwidth * sizeof(rgbtriple)) % 4) % 4 the outfile and infile have different widths so the padding is different! padding isn t an RGBTRIPLE we can t fread padding

26 writing padding fputc(chr, outptr); chr: char to write outptr: FILE * to write to fputc(0x00, outptr);

27 padding n = 2 RGBtriple RGBtriple 0x 00 0x 00

28 padding n = 2 RGBtriple RGBtriple 0x 00 0x 00 RGBtriple RGBtriple

29 padding n = 2 RGBtriple RGBtriple 0x 00 0x 00 RGBtriple RGBtriple RGBtriple RGBtriple

30 padding n = 2 RGBtriple RGBtriple 0x 00 0x 00 RGBtriple RGBtriple RGBtriple RGBtriple

31 padding = (4 (bi.biwidth * sizeof(rgbtriple)) % 4) % 4

32 what s changing? old bi.biwidth bi.biheight bi.bisizeimage bf.bfsize new bi.biwidth *= n bi.biheight *= n...?...?

33 what s changing? old bi.biwidth bi.biheight bi.bisizeimage bf.bfsize padding new bi.biwidth *= n bi.biheight *= n...?...?...?

34 pseudocode: resizing horizontally for each row for each pixel in row write to outfile n times write outfile's padding skip over infile's padding

35 TODO: þ open file þ update outfile s header info þ read infile s scanline, pixel by pixel þ resize horizontally þ remember padding! resize vertically

36 resize every pixel repeated n times every row repeated n times n = 3

37 resize every pixel repeated n times every row repeated n times n = 3

38 resize every pixel repeated n times every row repeated n times n = 3

39 resize every pixel repeated n times every row repeated n times n = 3

40 resize every pixel repeated n times every row repeated n times n = 3

41 resize every pixel repeated n times every row repeated n times n = 3

42 resize every pixel repeated n times every row repeated n times n = 2

43 resize every pixel repeated n times every row repeated n times n = 2

44 resize every pixel repeated n times every row repeated n times n = 2

45 resize every pixel repeated n times every row repeated n times n = 2

46 resize every pixel repeated n times every row repeated n times n = 2

47 resize every pixel repeated n times every row repeated n times n = 2

48 resize every pixel repeated n times every row repeated n times n = 2

49 resize every pixel repeated n times every row repeated n times n = 2

50 resize every pixel repeated n times every row repeated n times n = 2

51 resize vertically multiple ways to do this! 1. rewrite methods remember pixels in an array write array as many times as needed 2. re-copy methods go back to the start of the original scanline re-scale scanline

52 file position indicator fseek(inptr, offset, from); inptr: FILE * to seek in offset: number of bytes to move cursor from: SEEK_CUR (current position in file) SEEK_SET (beginning of file) SEEK_END (end of file)

53 pseudocode: rewrite method for each row for each pixel write to array n times for n times write array to outfile write outfile padding skip over infile padding

54 pseudocode: recopy method for each row for n-1 times write pixels, padding to outfile send infile cursor back write pixels, padding to outfile skip over infile padding

55 TODO þ open file þ update outfile s header info þ read infile s scanline, pixel by pixel þ resize horizontally þ remember padding! þ resize vertically

56 this was resize

TODO. parse float input update outfile s header info resize horizontally remember padding! resize vertically

TODO. parse float input update outfile s header info resize horizontally remember padding! resize vertically resize TODO parse float input update outfile s header info resize horizontally remember padding! resize vertically copy.c parses int input opens a file updates header info for outfile reads each scanline,