Method and system for providing substitute computer fonts

A method in a computer system for providing a substitute font for an unavailable font having characters with overall widths the unavailable font having a numerical characterization of its visual characteristics, the method comprising the steps of:

• receiving a request from a requesting program for a requested font;
• determining that the requested font is unavailable in the computer system;
• identifying one or more candidate fonts that are available within the computer system to replace the unavailable font having numerical characterizations of their visual characteristics that differ from that of the unavailable font by less than a preselected maximum distance;
• selecting a basis font from among the candidate fonts that has characters with overall widths, each of which is the sum of an extent width corresponding to the width of a visible portion of the character, a leading width corresponding to the width of blank space preceding the visible portion of the character, and a trailing width corresponding to the width of blank space succeeding the visible portion of the character;
• and
• for each character of the basis font, increasing or decreasing the leading width and trailing width, so that the overall width is equal to the overall width of the corresponding character of the unavailable font and so that the visual appearance of each character of the basis font is not changed
• wherein when the requesting program displays characters using the basis font with the increased or decreased leading widths and trailing widths the characters are displayed with overall widths that are equal to the overall widths of the corresponding character of the unavailable font without further increasing or decreasing of the overall widths of the dismayed characters.

A method in a computer system for creating a substitute font for an unavailable font using available fonts whose characters each have an overall width that is the sum of an extent corresponding to the width of a visible portion of the character, a leading width corresponding to the width of blank space preceding the visible portion of the character, and a trailing width corresponding to the width of blank space succeeding the visible portion of the character, one or more of the available fonts being horizontally scalable, the method comprising the steps of:

• receiving a request from a requesting program for a requested font;
• determining that the requested font is unavailable in the computer system;
• determining whether the overall width of each character of an available font selected to replace the requested font is within a predetermined tolerance of the overall width of the corresponding character of the unavailable font;
• if it is determined that the overall width of each character of an available font is within the predetermined tolerance of the overall width of the corresponding character of the unavailable font, increasing or decreasing the leading and trailing widths of each character of that available font so that the overall width of each character of that available font is equal to the overall character width of the corresponding character of the unavailable font and so that the visual appearance of each character of the basis font is not changed and wherein when the requesting program displays characters using the basis font with the increased or decreased leading widths and trailing widths, the characters are displayed with overall widths that are equal to the overall widths of the corresponding character of the unavailable font without further increasing or decreasing of the overall width of the displayed characters;
• and
• if it is determined that none of the available fonts has characters whose overall widths are all within the predetermined tolerance of the overall widths of the corresponding characters of the unavailable font, horizontally scaling the characters of a selected horizontally scalable font go that the overall width of each character of the selected font is equal to the overall width of the corresponding character of the unavailable font.

A method in a computer system for creating a substitute font for an unavailable font using available fonts whose characters each have an overall height that is the sum of an extent corresponding to the height of a visible portion of the character, an upper height corresponding to the height of blank space above the visible portion of the character, and a lower height corresponding to the width of blank space below the visible portion of the character, one or more of the available fonts being vertically scalable, the method comprising the steps of:

• receiving a request from a requesting program for a requested font;
• determining that the requested font is unavailable in the computers system;
• determining whether the overall height of each character of a selected available font to replace the requested font is within a predetermined tolerance of the overall height of a corresponding character of the unavailable font, the selected available font having a character that corresponds to each of the characters of the requested font;
• if it is determined that the overall height of each character of an available font is within the predetermined tolerance of the overall height of the corresponding character of the unavailable font, increasing or decreasing the upper and lower heights of each character of that available font so that the overall height of each character of that available font is the same as the overall height of the corresponding character of the unavailable font and so that the visual appearance of each character of the available font is not changed and wherein when the requesting program displays characters using the available font with the increased or decreased upper heights and lower heights, the characters are displayed with overall heights that are equal to the overall heights of the corresponding character of the unavailable font without further increasing or decreasing of the overall heights of the displayed characters;
• and
• if it is determined that none of the available fonts has characters whose overall heights are all within the predetermined tolerance of the overall heights of the corresponding characters of the unavailable font, vertically scaling the characters of a selected vertically scalable font so that the overall height of each character of the selected font is the same as the overall height of the corresponding character of the unavailable font.

A method in a computer system for providing a substitute font for an unavailable font having characters with overall widths, the method comprising the steps of:

• receiving a request from a requesting program for a requested font;
• determining that the requested font is unavailable in the computer system;
• selecting a font to replace the requested font having characters with vertical stems and overall widths that is available within the computer system, the vertical stems each having a width measured horizontally, the overall widths including a leading width, an extent width and a trailing width;
• scaling the characters of the selected font horizontally to match the overall character widths of the unavailable font without adjusting the extent width of the characters so that the visual appearance of each character is not changed;
• resizing the scaled characters of the selected font both horizontally and vertically to match a requested height;
• and
• modifying the vertical stem widths of the resized characters of the selected font so that the vertical stem width of every resized character is the same
• wherein when the requesting program displays characters using the selected font after its characters have been scaled, resized, and modified, the characters are displayed with overall widths that match the overall widths as if the characters were displayed in the requested font, resized to the requested height without further adjusting of the overall widths of the displayed characters.

A method in a computer system for creating a substitute font for an unavailable font using available fonts whose characters each have at overall width that is the sum of an extent corresponding to the width of a visible portion of the character, a leading width corresponding to the width of blank space preceding the visible portion of the character, and a trailing width corresponding to the width of blank space succeeding the visible portion of the character, one or more of the available fonts being horizontally scalable, the method comprising the steps of:

• receiving a request from a requesting program for a requested font;
• determining that the requested font is unavailable in the computer system;
• identifying available fonts with appearances that are similar to the appearance of the unavailable font;
• for each of the identified fonts, in the order of the identified fonts' similarity to the unavailable font, determining whether the overall width of each character of the identified font is within a predetermined tolerance of the overall width of the corresponding character of the unavailable font;
• if it is determined that the overall width of each character of an identified font is within the predetermined tolerance of the overall width of the corresponding character of the unavailable font:
• retrieving the identified font whose characters' overall widths were determined to be within a predetermined tolerance of the overall widths of the corresponding characters of the unavailable font, and
• increasing or decreasing the leading and trailing widths of each character of the retrieved font so that the overall width of each character of the retrieved font is equal to the overall width of the corresponding character of the unavailable font and so that the visual appearance of each character of the retrieved font is not changed and wherein when the requesting program displays characters using the retrieved font with the increased or decreased leading widths and trailing widths, the characters are displayed with overall widths that are equal to the overall widths of the corresponding character of the unavailable font without further increasing or decreasing of the overall widths of the displayed characters;
• and
• if it is determined that none of the available fonts has characters whose overall widths are all within the predetermined tolerance of the overall widths of the corresponding characters of the unavailable font:
• selecting a horizontally scalable font,
• retrieving the selected font,
• horizontally scaling the characters of the selected font so that the overall width of each character of the selected font is equal to the overall width of the corresponding character of the unavailable font, and
• regularizing the appearance of the horizontally scaled characters of the selected font.

An apparatus for providing a substitute font that visually approximates a requested font that is unavailable in the computer system, the requested font and the substitute font having respective sets of characters each of which have an overall width, the overall width having a leading width, an extent width, and a trailing width, the requested font and the substitute font being outline fonts, the apparatus comprising:

• means for receiving a request from a requesting program for a requested font;
• means for determining that the requested font is unavailable in the computer system;
• means for selecting as the substitute font to replace the requested font a font that is available in the computer system;
• means for adjusting the overall widths of the characters of the substitute font to match the overall widths of corresponding characters of the requested font by adjusting the leading and trailing widths without adjusting the extent width so that the visual appearance of each character of the substitute font is not changed;
• and
• means for making the substitute font with the overall widths of the characters adjusted to match the overall widths of the requested font available to the requesting program so that when the requesting program displays characters using the substitute font and without further adjustment of the overall widths of the characters, the characters are displayed with overall widths that match the overall widths as if the characters had been displayed using the requested font.

An apparatus for providing a substitute font for an unavailable font having characters with overall widths, the apparatus comprising:

• means for receiving a request from a requesting program for a requested font;
• means for determining that the requested font is unavailable in the computer system;
• means for identifying one or more candidate fonts that are available within the computer system to replace the unavailable font having compact numerical characterizations that differ from that of the unavailable font by less than a preselected maximum distance;
• means for selecting a font from among the candidate fonts that has characters with overall widths, each of which is the sum of a leading width, an extent width, and a trailing width;
• and
• means for increasing or decreasing the leading width and trailing width for each character of the selected font without adjusting the extent width, so that the overall width is equal to the overall width of the corresponding character of the unavailable font and so that the visual appearance of each character of the selected font is not changed
• wherein when the requesting program displays characters using the selected font with the increased or decreased leading widths and trailing widths, the characters are displayed with overall widths that are equal to the overall width of the corresponding character of the unavailable font without further increasing or decreasing of the overall widths of the displayed characters.

An apparatus for creating a substitute font for an unavailable font using available fonts whose characters each have an overall width that is the sum of an extent width corresponding to the width of a visible portion of the character, a leading width corresponding to the width of blank space preceding the visible portion of the character, and a trailing width corresponding to the width of blank space succeeding the visible portion of the character, one or more of the available fonts being horizontally scalable, the apparatus comprising:

• means for receiving a request from a requesting program for a requested font;
• means for determining that the requested font is unavailable in the computer system;
• means for determining whether the overall width of each character of a selected available font to replace the requested font is within a predetermined tolerance of the overall width of the corresponding character of the unavailable font;
• means for increasing or decreasing the leading and trailing widths of each character of that available font so that the overall width of each character of that available font is equal to the overall character width of the corresponding character of the unavailable font if it is determined that the overall width of each character of an available font is within the predetermined tolerance of the overall width of the corresponding character of the unavailable font so that the visual appearance of each character of the available font is not changed and wherein when the requesting program displays characters using the available font with the increased or decreased leading widths and trailing widths, the characters are displayed with overall widths that are equal to the overall widths of the corresponding character of the unavailable font without further increasing or decreasing of the overall widths of the displayed characters;
• and
• means for horizontally scaling the characters of a selected horizontally scalable font so that the overall width of each character of the selected font is equal to the overall width of the corresponding character of the unavailable font if it is determined that none of the available fonts has characters whose overall widths are all within the predetermined tolerance of the overall widths of the corresponding characters of the unavailable font.

An apparatus for creating a substitute font for an unavailable font using available fonts whose characters each have an overall height that is the sum of all extent corresponding to the height of a visible portion of the character, an upper height corresponding to the height of blank space above the visible portion of the character and a lower height corresponding to the width of blank space below the visible portion of the character, one or snore of the available fonts being vertically scalable, the apparatus comprising:

• means for receiving a request from a requesting program for a requested font;
• means for determining that the requested font is unavailable in the computer system;
• means for determining whether the overall height of each character of a selected available font to replace the requested font is within a predetermined tolerance of the overall height of the corresponding character of the unavailable font;
• means for increasing or decreasing the upper and lower heights of each character of that available font so that the overall height of each character of that available font is equal to the overall character height of the corresponding character of the unavailable font if it is determined that the overall height of each character of an available font is within the predetermined tolerance of the overall height of the corresponding character of the unavailable font and so that the visual appearance of each character of the available font is not changed wherein when the requesting program displays characters using the available font with the increased or decreased upper heights and lower heights, the characters are displayed with overall heights that are equal to the overall heights of the corresponding character of the unavailable font without further increasing or decreasing of the overall heights of the displayed characters;
• and
• means for vertically scaling the characters of a selected vertically scalable font so that the overall height of each character of the selected font is equal to the overall height of the corresponding character of the unavailable font if it is determined that none of the available fonts has characters whose overall heights are all within the predetermined tolerance of the overall heights of the corresponding characters of the unavailable font.

A computer-readable medium containing instructions for causing a computer system to provide a substitute font that visually approximates a requested font that is unavailable in the computer system, the requested font and the substitute font having respective sets of characters each of which have an overall width, the overall width having a leading width, an extent width, and a trailing width, the requested font and the substitute font being outline fonts, by:

• receiving a request for a requested font;
• and
• when the requested font is unavailable,
• selecting as the substitute font to replace the requested font a font that is available;
• adjusting the overall widths of the characters of the substitute font to match the overall widths of corresponding characters of the requested font by adjusting the leading and trailing widths so that the visual appearance off each character of the substitute font is not changed;
• and
• making the substitute font with the overall widths of the characters adjusted to match the overall widths of the requested font available for use in place of the requested font so that when the requesting program displays characters using the substitute font and without further adjustment of the overall widths of the characters, the characters are displayed with overall widths that match the overall widths as if the characters had been displayed using the requested font.

A computer-readable medium containing instructions for causing a computer system to provide a substitute font for an unavailable font having characters with overall widths, the unavailable font having a numerical characterization of its visual characteristics, by:

• receiving a request for a requested font;
• and
• when the requested font is unavailable,
• identifying one or more candidate fonts that are available to replace the unavailable font having numerical characterizations of their visual characteristics that differ from that of the unavailable font by less than a preselected maximum distance;
• selecting a basis font from among the candidate fonts that has characters with overall widths, each of which is the sum of an extent width corresponding to the width of a visible portion of the character, a leading width corresponding to the width of blank space preceding the visible portion of the character, and a trailing width corresponding to the width of blank space succeeding the visible portion of the character;
• and
• for each character of the basis font, increasing or decreasing the leading width and trailing width, so that the overall width is equal to the overall width of the corresponding character of the unavailable font and so that the visual appearance of each character of the basis font is not changed
• wherein when the requesting program displays characters using the basis font with the increased or decreased leading widths and trailing widths the characters arc displayed with overall widths that are equal to the overall widths of the corresponding character of the unavailable font without further increasing or decreasing of the overall widths of the displayed characters.