Image format conversion with transparency color adjustment
AssigneeCompaq Computer Corporation
InventorsJeffrey R. Gabler, Darrell J. Starnes
Life of this patent
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Abstract
Improved image format conversion techniques that provide improved conversion from an image format supporting transparency to an image format not supporting transparency. The techniques replace a transparency color in an original image format prior to format conversion. Consequently, the format conversion uses the replacement transparency color instead of the original transparency color, and thus is able to provide improved image conversion when converting from an image format supporting transparency to an image format not supporting transparency.
Claims19
A method for converting a source image file having a first image format to a target image having a second image format, the method comprising the acts of:
- (a) determining whether the source image file having the first image format uses at least one transparent portion;
- (b) receiving a color table from the source image file;
- (c) identifying a transparent color for the at least one transparent portion from the color table;
- (d) determining a replacement transparent color for use with the target image having the second image format;
- (e) modifying the color table by substituting the replacement transparent color for the transparent color;
- and
- (f) thereafter converting the source image file having the first image format to the target image file having the second image format in accordance with the modified color table.
A method for converting a source image file having a first image format to a target image having a second image format, the method being performed by a computer system including a memory, the method comprising the acts of:
- (a) allocating a memory block in the memory of the computer system;
- (b) reading a header block from the source image file;
- (c) reading a logical screen descriptor block from the source image file;
- (d) determining whether a color table is present in the source image file;
- (e) reading the color table into the memory block when the determining (d) determines that the color table is present in the source image file;
- (f) reading a graphic control block for an image block in the source image file;
- (g) determining whether transparency is used in the image block by an examination of the graphic control block;
- (h) identifying a transparent color index for the color table;
- (i) determining a replacement transparent color for use with the target image having the second image format, where the second image format does not support transparency;
- (j) modifying the color table by substituting the replacement transparent color for the transparent color;
- and
- (k) thereafter converting the source image file having the first image format to the target image file having the second image format in accordance with the modified color table.
A computer readable medium containing computer program code for converting a source image file having a first image format to a target image having a second image format, said computer readable medium comprising:
- computer program code for receiving the source image file having with the first image format that uses at least one transparent portion;
- computer program code for receiving a color table from the source image file;
- computer program code for identifying a transparent color for the at least one transparent portion from the color table;
- computer program code for determining a replacement transparent color for use with the target image having the second image format;
- computer program code for modifying the color table by substituting the replacement transparent color for the transparent color;
- and
- computer program code for converting the source image file having the first image format to the target image file having the second image format in accordance with the modified color table.
Dependencies are inferred from the claim text.