Font conversion device

Claim 2

A font conversion device for converting a first font formed of a first plurality of pixels each having a binary value, to a second font, smaller than said first font, formed of a second plurality of pixels, each having a multilevel value, said device comprising: source font means for providing font data; corresponding to said first plurality of pixels in respective regions of said first font; spatial operation means for reducing said font data by applying a low pass filtering to said font data read out from said respective regions of said first font to produce a plurality of multilevel-value font data having a first dynamic range, each of said multilevel-value font data corresponding to a respective one of said second plurality of pixels; and a gradation correction means for applying a predetermined gain to said plurality of multilevel-value data to produce each multilevel value with a second dynamic range larger and with a greater maximum value than said first dynamic range.

Claim 3

A font conversion device as claimed in claim 1, wherein said predetermined gain is greater than the inverse number of the maximums of said plurality of multilevel-value font data.

Claim 4

A font conversion device as claimed in claim 1, further comprising a gamma correction means for correcting said multilevel-value font data, said gamma correction means setting a gamma correction characteristics desirable to the gradation characteristics of the font outputting device.

Claim 5

A font conversion device as claimed in claim 1, wherein said gradation correction means comprising a ROM table storing plural input/output characteristics therein.

Claim 6

A font conversion device as claimed in claim 4, further comprising a gradation characteristics setting means for setting the input/output characteristics of said gradation correction means.

Claim 7

A font conversion device as claimed in claim 5, wherein said gradation characteristics setting means examines the distribution of said multilevel-value data and sets desirable input/output characteristics based on the result of said examination.

Claim 8

A font conversion device as claimed in claim 6, wherein said gradation characteristics setting means sets the input/output characteristics corresponding to the result of said examination applied to all characters of said binary source font.

Claim 9

A font conversion device as claimed in claim 5, wherein said gradation characteristics setting means sets the input/output characteristics based on said predetermined reduction rate.

Claim 10

A font conversion device as claimed in claim 5, wherein said gradation characteristics setting means sets the input/output characteristics based on the typeface of said multilevel-value data.

Claim 11

A font conversion device as claimed in claim 1, wherein said gradation correction means comprising a RAM table being able to receive a plural input/output characteristics provided by said control means.

Claim 12

A font conversion device as claimed in claim 1, further comprising a vector font rasterizing means for generating said binary font data from a vector font data.

Claim 13

A font conversion device as claimed in claim 11, wherein said vector font rasterizing means generates said binary font data having a font size greater than the pixel area defined by (kk×n)×(kk×n), in which the font size finally output is expressed by n×n pixels, the number of gradation levels of said binary font data input is k, and square root of k is kk.

Claim 14

A font conversion device as claimed in claim 1, wherein said source font means is comprised of a font ROM for storing said binary font data therein.

Claim 15

A font conversion device as claimed in claim 13, wherein said font ROM further stores at least information of gradation correction characteristics, and said device further includes a gradation characteristics setting means for setting the characteristics of said gradation correction means based on said information.

Claim 16

A font conversion device as claimed in claim 1, further comprising a gradation characteristics setting means for setting the input/output characteristics of said gradation correction means.

Claim 17

A font conversion device as claimed in claim 1, wherein said predetermined gain is one or greater.

Claim 18

A font conversion device for converting a binary font data formed by pixels, said pixels having a binary value, by applying a bandwidth limitation according to a predetermined reduction rate, into a reduced font data formed by pixels each having multilevel values for display on an output device having a first dynamic range, said device comprising: source font means for sequentially providing font data of predetermined areas of said binary font data, said predetermined area including a predetermined number of pixels; spatial operation means for reducing said binary font data by applying a low pass filtering to said binary font data read out from said predetermined areas to produce a plurality of multilevel-value font data, each of said multilevel-value font data representing a single pixel of said reduced font data; and gradation correction means for applying a gain to said plurality of multilevel-value data to produce an enhanced font data having a second dynamic range larger and with a greater maximum value than said first dynamic range, said gain related to the first dynamic range of the output device; and control means for controlling each means of said font conversion device.

Claim 19

A font conversion device for converting a binary font data formed by pixels, said pixels having a binary value, by applying a bandwidth limitation according to a predetermined reduction rate, into a reduced font data formed by pixels each having multilevel values for display on an output device having a first dynamic range, said device comprising: source font means for sequentially providing font data of predetermined areas of said binary font data, said predetermined area including a predetermined number of pixels; spatial operation means for reducing said binary font data by applying a low pass filtering to said binary font data read out from said predetermined areas to produce a plurality of multilevel-value font data, each of said multilevel-value font data representing a single pixel of said reduced font data; and gradation correction means for applying a gain to said plurality of multilevel-value data to produce an enhanced font data having a second dynamic range larger and with a greater maximum value than said first dynamic range, said gain related to the first dynamic range of the output device; and control means for controlling each means of said font conversion device.

Claim 20

A font conversion device for converting a first font formed of a first plurality of pixels each having a binary value, to a second font, smaller than said first font, formed of a second plurality of pixels, each having a multilevel value, said device comprising: a first memory for providing font data; corresponding to said first plurality of pixels in respective regions of said first font; a low pass filter for reducing said font data read out from said respective regions of said first font to produce a plurality of multilevel-value font data having a first dynamic range, each of said multilevel-value font data corresponding to a respective one of said second plurality of pixels; and a gradation corrector for applying a predetermined gain to said plurality of multilevel-value data to produce each multilevel value with a second dynamic range larger and with a greater maximum value than said first dynamic range.

Claim 21

A font conversion device for converting a first font formed of a first plurality of pixels each having a binary value, to a second font, smaller than said first font, formed of a second plurality of pixels, each having a multilevel value, said device comprising: a first memory for providing font data; corresponding to said first plurality of pixels in respective regions of said first font; a low pass filter for reducing said font data read out from said respective regions of said first font to produce a plurality of multilevel-value font data having a first dynamic range, each of said multilevel-value font data corresponding to a respective one of said second plurality of pixels; and a gradation corrector for applying a predetermined gain to said plurality of multilevel-value data to produce each multilevel value with a second dynamic range larger and with a greater maximum value than said first dynamic range.

Claim 24

The method of claim 19, wherein said first plurality of pixels each have a binary value and wherein said second plurality of pixels each have a multilevel-value.