Adjusting contrast in anti-aliasing
First Claim
1. A computer-implemented method for processing a character for anti-aliased display on a raster output device where the character is created at a type size by a font having font metrics including a standard stem width, the method comprising:
- computing a set of density values to provide one density value for each of a set of raster positions to represent the character on the raster output device; and
comparing (i) the standard stem width scaled to the type size to (ii) a threshold value, and if the threshold value is exceeded increasing at least one of the density values in the computed set of density values, thereby compensating for fading that may occur in the display of the character on the raster output device.
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Accused Products
Abstract
A method and apparatus for processing a character for anti-aliased display on a raster output device. A set of density values is computed for a set of raster positions to represent the character and the density values of the set are scaled to extend their range upward toward a maximum density value, whereby generally at least one of the density values of the set becomes the maximum density value. In one embodiment, the set of density values is computed from a rendering of the character at resolution higher than the resolution of the output device. In another embodiment, the character is created by a font having font metrics including a reference dimension, and the density values are scaled by computing adjusted values as a non-decreasing function of the original values, the function being defined to compute a maximum adjusted density value for at least one non-maximum density value.
57 Citations
24 Claims
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1. A computer-implemented method for processing a character for anti-aliased display on a raster output device where the character is created at a type size by a font having font metrics including a standard stem width, the method comprising:
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computing a set of density values to provide one density value for each of a set of raster positions to represent the character on the raster output device; and comparing (i) the standard stem width scaled to the type size to (ii) a threshold value, and if the threshold value is exceeded increasing at least one of the density values in the computed set of density values, thereby compensating for fading that may occur in the display of the character on the raster output device. - View Dependent Claims (2, 3)
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4. A computer-implemented method for processing a character for anti-aliased display on a raster output device having an output resolution and one or more output pixel positions for display of the character, the character being created at a type size by a font having font metrics including a reference dimension, the method comprising:
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rendering the character at a resolution higher than the output resolution; computing a set of original density values, one for each output pixel position used to display the character, from the rendering, wherein the set of original density values includes a highest density value; computing an adjusted density value for at least one computed original density value by applying an adjustment function to the original density value, the adjustment function being defined to compute an adjusted density value having a maximum value when the adjustment function is applied to the highest density value; and comparing (i) the reference dimension scaled to the type size to (ii) a threshold value, and bypassing the step computing an adjusted density value if the threshold value is exceeded. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A computer-implemented method for processing a character for anti-aliased display on a raster output device having an output resolution and one or more output pixel positions for display of the character, the character being created at a type size by a font having font metrics including a reference dimension, the method comprising:
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rendering the character at a resolution higher than the output resolution; computing a set of original density values, one for each output pixel position used to display the character, from the rendering, wherein the set of original density values includes a highest density value; and computing an adjusted density value for at least one computed original density value by applying an adjustment function to the original density value, where the adjustment function is a function of the original density value and an index value and where the index value is approximately a maximum density value times the reference dimension scaled to the type size divided by a threshold stem width, the adjustment function being defined to compute a maximum value when applied to an original density value that is greater than or equal to the index value. - View Dependent Claims (11, 12)
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13. A storage device readable by a machine, tangibly embodying a set of computer-readable computer program instructions comprising instructions for processing a character for anti-aliased display on a raster output device where the character is created at a type size by a font having font metrics including standard stem width, the set of instructions comprising:
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instructions for computing a set of density values for a set of raster positions to represent the character; and instructions for comparing (i) the standard stem width scaled to the type size to (ii) a threshold value, and if the threshold value is exceeded increasing at least one of the density values of the set thereby compensating for fading that may occur in the display of the character on the raster output device. - View Dependent Claims (14, 15)
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16. A storage device readable by a machine, tangibly embodying a set of computer-readable computer program instructions comprising instructions for processing a character for anti-aliased display on a raster output device having an output pixel position, the character being created at a type size by a font having font metrics including a reference dimension, the set of instructions comprising:
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instructions for rendering the character at a resolution higher than the output resolution; instructions for computing a set of original density values, one for each output pixel position, from the rendering, wherein the set of original density values includes a highest density value; instructions for computing an adjusted density value for at least one computed original density value by applying an adjustment function to the original density value, the adjustment function being defined to compute an adjusted density value having a maximum density value when the adjustment function is applied to the highest density value; and instructions for comparing (i) the reference dimension scaled to the type size to (ii) a threshold value, and bypassing the step of computing an adjusted density value if the threshold value is exceeded. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A storage device readable by a machine, tangibly embodying a set of computer-readable computer Program instructions comprising instructions for processing a character for anti-aliased display on a raster output device having an output pixel position, the character being created at a type size by a font having font metrics including a reference dimension, the set of instructions comprising:
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instructions for rendering the character at a resolution higher than the output resolution; instructions for computing a set of original density values, one for each output pixel position, from the rendering, wherein the set of original density values includes a highest density value; and instructions for computing an adjusted density value for at least one computed original density value by applying an adjustment function to the original density value, the adjustment function is a function of the original density value and an index value and where the index value is approximately a maximum density value times the reference dimension scaled to the type size divided by a threshold stem width, the adjustment function being defined to compute a maximum density value when applied to an original density value that is greater than or equal to the index value. - View Dependent Claims (23, 24)
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Specification