bit map file format
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By: Darshika Desai
ID: 09BCA24
Bitmap File Format
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Bitmap File Formats
It is windows image format and its extension is.bmp.
It supports only RGB color.
Bitmap image format does not support animationsand not preferred for the internet application.
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Bitmap file structure
Each bitmap file contains
A bitmap-file header,
A bitmap-information header,
A color-table, and
A array of bytes that defines the bitmap bits.
A .bmp file contains of the following data
structures:
BITMAPFILEHEADER bmfh; BITMAPINFOHEADER bmih;
RGBQUAD AColors[];
BYTE ABitmapBits[];
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bmfh
Header of bitmap file.
bmih
Header of bitmap information.
AColor[]
Color table.
ABitmapBits[]
Detail of the bits.
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The detailed structure of the bitmap file in shownin following table:
BitmapFileHeader
Start
Positio
n
Size
(in
bytes)
Name of
the Field
Standard
value
Description
1 2 bfType 19778 Signature of Bitmap file
3 4 bfSize ?? Size of the file in bytes7 2 bfReserved
1
0 Reserved bit, always set to
zero
9 2 bfReserved
2
0 Reserved bit, always set to
zero
11 4 bfoffbits 1078 Specifies the offset from thebeginning of the file.
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BitmapinfoHeader
Start
Position
Size (in
bytes)
Name of
Field
Standard
value
Description
15 4 BiSize 40 Size of the
BITMAPINFOHEADE
R structure
19 4 BiWidth 100 Width of the image in
pixel
23 4 BiHeight 100 Height of the image in
pixel
27 2 BiPlanes 1 Number of planes of
the target device
29 2 biBitCount 8 Specifies the depth ofthe bits per pixel
31 4 biCompresssi
on
0 Type of the
compression.
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Start
Position
Size (in
bytes)
Name of Field Standar
d value
Description
35 4 biSizeImage 0 Size of the image in
bytes
39 4 biXPelsPerMet
er
0 Horizontal pixel per
meter
43 4 biYPelsPerMet
er
0 Vertical pixel per
meter
47 4 biClrUsed 0 The color depth
used in the bitmap
51 4 biCLrImportant 0 The number of the
color that are
important for the
bitmap
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RGBQuad of bitmap
Start Size Name of the
Field
Description
1 1 rgbBlue Blue part ofthe color
2 1 rgbGreen Green part
of the color
3 1 rgbRed Red part of
the color
4 1 rgbReserved Reserved
byte must be
always set to
zero
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