(12) United States Patent
`(10) Patent N0.:
`US 6,700,589 B1
`
`Canelones et al.
`(45) Date of Patent:
`Mar. 2, 2004
`
`U5006700589B1
`
`(54) METHOD, SYSTEM, AND PROGRAM FOR
`MAGNIFYING CONTENT DOWNLOADED
`FROM A SERVER OVERA NETWORK
`.
`-
`Inventors galfigagfigfiiflesbifiiafi Park’
`.
`’
`.
`,y
`3"
`Au5t¥n> TX (US)> Rablfldmnath Dumb
`Austin, TX (US); Kelvm R. Lawrence,
`Round Rock, TX (US)
`
`(75)
`
`. 345/428
`6,128,021 A * 10/2000 van der Meulen et al.
`6,157,935 A * 12/2000 Tran et al.
`.................. 382/187
`
`6,202,060 B1 *
`3/2001 Tran .............
`707/104.1
`8/2001 Slvan et al. ........... 345/21
`6,281,874 B1 *
`
`6,396,507 B1 *
`5/2002 Kaizuka et al.
`345/661
`
`6,396,941 B1 *
`5/2002 Bacus etal.
`......
`382/128
`
`9/2002 Johnson ...................... 382/239
`6,453,073 B2 *
`6,496,189 B1 * 12/2002 Yaron et al.
`................ 345/428
`
`FOREIGN PATENT DOCUMENTS
`
`(73) Assignee:
`
`International Business Machines
`Corporation, Armonk, NY (US)
`
`$3
`JP
`
`121384213?
`11175709
`
`31333
`7/1999
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U‘S’C’ 154(b) by 0 days.
`
`(21) APP1~ N0~3 09/506,236
`
`(22)
`
`Filed:
`
`Feb. 17, 2000
`
`Int. Cl.7 ............................ G09G 5/00, G06F 17/30
`(51)
`(52) US. Cl.
`.......................................... 345/660; 707/10
`(58) Field of Search ................................. 345/660, 661,
`345/2.1; 707/10, 104.1; SSS/1.18
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`1/1989 Yeomans .................... 345/661
`4,800,379 A *
`
`.. 382/149
`1/1991 Norwood et al.
`.....
`4,985,927 A
`.............. 382/254
`4/1995 Banton et al.
`5,404,411 A
`2/1998 Akins, III etal.
`.
`.. 725/142
`5,715,515 A
`9/1998 Nielsen .............
`725/37
`5,805,153 A
`1/1999 Rowe et al.
`.......
`.. 707/526
`5,860,074 A
`3/1999 DeAguiar et al.
`.......... 345/511
`RE36,145 E *
`3/1999 Ferriere .............
`358/426
`5,880,856 A *
`9/1999 Gordon
`345/467
`5,959,609 A
`5,974,431 A * 10/1999 lida .........
`345/629
`6,006,231 A * 12/1999 Popa .............
`707/10
`6,067,553 A *
`5/2000 Downs et al.
`............. 358/1.18
`
`
`
`
`
`* cited by examiner
`Primary Examiner Michael Razavi
`Assistant Examiner—Ryan Yang
`(74) Attorney, Agent, or Firm—David W. Victor; Konrad
`Raynes Victor & Mann
`
`(57)
`
`ABSTRACT
`
`Disclosed is a system, method, and program for magnlfylng
`displayed content downloaded from a server over a network.
`Information is received indicating selection of a region of
`the displayed content to magnify. Adetermination is made of
`at least one region of the selected region including image
`content. The server maintains a high resolution file version
`and a low resolution file version of the image content. A
`determination is then made as to whether the selected image
`content from the displayed image file is the low resolution
`file version. If so, a command is generated to retrieve from
`the server specific byte locations from the high resolution
`file version including the image content
`in the selected
`region. The specified bytes are less than all the image data
`bytes in the high resolution version of the file if the image
`content in the selected region comprises less than all of the
`image content maintained in the high resolution version of
`the file.
`
`30 Claims, 3 Drawing Sheets
`
`2
`
`.1
`
`
`
`
`
`User Computer
`
`4
`
`
`
`
`
`Content Server 14
`
`Content
`Database
`
`
`
`
`HTI'P
`Server
`
`Google 1023
`US. Patent No. 9,445,251
`
`Google 1023
`U.S. Patent No. 9,445,251
`
`

`

`US. Patent
`
`Mar. 2, 2004
`
`Sheet 1 0f3
`
`US 6,700,589 B1
`
`2
`
`User Computer
`
`4
`
`Server
`
`Content Server
`
`14
`
`Content
`
`Database
`
`I HTTP
`
`

`

`US. Patent
`
`Mar. 2, 2004
`
`Sheet 2 0f3
`
`US 6,700,589 B1
`
`100
`
`
`
`
`Receive coordinates of user
`
`selected area of displayed HTML
`
`
`page and magnification factor
`to apply to selected area.
`
`
`
`102
`
`
`
`Does
`selected area
`
`include an image
`
`region?
`
`
`
`Yes —>
`
`
`
`No
`
`
`124
`
` Does
`selected area
`
`include text
`
`region(s)?
`
`
`
`
`
`
`Map bit map font
`ls text
`to a corresponding
`
`in a vector
`
`
`vector font.
`font?
`
`
`
`
`No
`
`
`
`Magnify text by applying
`
`
`magnification factor to vector
`
`fonts comprising text.
`
`
`
`Display magnified text
`and/or image in browser.
`
`132
`
`

`

`US. Patent
`
`Mar. 2, 2004
`
`Sheet 3 0f3
`
`US 6,700,589 B1
`
`
`
`Determine pixel expansion ratio as
`number of pixels in high resolution
`image per pixel in low resolution image.
`
`
`
`
`
`Does
`
`image header
`
`
`indicate high resolution
`
`
`counterpart of
`
`image?
`
`
`Perform requested
`magnification
`
`operation on high
`
`
`
`resolution pixel bytes
`No
`108
`
`
`
`
`
`
`
`
`
`
`
`
`
`110
`
`114
`
`Determine byte offsets in pixel
`data area of the start and end
`ranges of bytes that include the
`
`
`
`pixels of the selected area
`
`
`
`in low resolution image file.
`
`
`
`
`
`
`
`Multiply each determined offset by the pixel
`
`expansion ratio to determine the start and end
`
`
`offsets of bytes that include pixels of the
`
`
`selected areas in the high resolution image file.
`
`
`
`Add bytes in the header and color table
`
`
`parts of image file to offsets to determine
`byte location in high resolution file that
`
`include pixels of the selected area.
`
`
`
`Generate HTTP GET request with
`
`range header to retrieve bytes within
`determined byte offset ranges.
`
`
`
`
`
`
`
`
` 118
`
`Receive pixel
`bytes from
`high resolution
`section image.
`
`
`
`Send HTTP GET request specifying
`ranges of bytes to content server.
`
`

`

`US 6,700,589 B1
`
`1
`
`METHOD, SYSTEM, AND PROGRAM FOR
`MAGNIFYING CONTENT DOWNLOADED
`FROM A SERVER OVER A NETWORK
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates to a method, system, and
`program for magnifying displayed content downloaded from
`a server over a network and, in particular, displayed content
`including images and text.
`2. Description of the Related Art
`One of the rapidly expanding sources of information and
`documentation is the “World Wide Web” (WWW) or Inter-
`net. Many documents that are available on the Web are
`images. Images generally are substantially larger files than
`text files and take longer to download due to the larger file
`size of images and the limitations of Internet bandwidth.
`Network delays resulting from overloading network servers
`or the communication lines are one of the major customer
`complaints about network access.
`One of the most popular image viewing tools is a mag-
`nification tool which allows the user to enlarge or reduce the
`size of the image. However, Internet content providers that
`provide images that users may want
`to magnify face a
`dilemma. If they want to reduce download times, then they
`must limit the resolution of the image users download as a
`higher resolution image requires more pixels of information,
`hence creating larger files. However, the lower the resolution
`of an image, the poorer the image quality as the image is
`enlarged using a magnification tool. On the other hand, to
`improve the quality of magnified images, the Internet con-
`tent provider would have to increase the resolution of the
`image and, hence, the file size. Increasing the file size to
`improve resolution during magnification operations will
`increase network delays to download the files, reduce net-
`work bandwidth and result in consumer dissatisfaction with
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`the lengthy download times associated with the content
`provider’s Web site.
`One solution to the above dilemma is for the content
`
`40
`
`the
`provider to perform the magnification operations at
`server, and then send the image at the requested magnifica-
`tion to the user computer. For instance, Mapquest.com, Inc.
`allows users to download a section of a map showing a street
`address. The user using a “Zoom” tool may select to enlarge
`or reduce the current view of the street map. When the user
`changes the magnification level, the server is contacted and
`the new magnification level is downloaded to the user. Thus,
`any magnification, i.e., expansion or reduction, of the bit
`map is performed at the content provider (Mapquest) server.
`In this way, the content provider need not provide the user
`the highest resolution image of the map, but may initially
`provide a lower resolution image to reduce delays in down-
`load times. If the user wants to enlarge the view,
`then
`Mapquest sends a higher resolution magnified view of a
`smaller area. This further limits the size of the file as the
`
`portion of the image enlarged is less than the portion of the
`image previously viewed. Thus, the overall file size of the
`image may not increase because the user is not presented a
`higher resolution view of the entire previous lower resolu-
`tion image, but is instead provided a higher resolution view
`of a smaller area of the previous image.
`Although the above approach may help limit the file size
`of the higher resolution image, there are still drawbacks with
`the server oriented approach where the user must contact the
`content provider’s site to obtain a new magnified level of the
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`image. First, is that for each change in magnification, the
`user must contact the service provider’s site. This may result
`in the user experiencing further network delays. Further,
`performing the zoom operations at the server would increase
`processing burdens on the server that may overload the
`server processor, thereby causing delays in responding to
`Internet document requests that are unrelated to bandwidth
`issues. Still further, the user may have wanted a magnified
`view of the entire image area at the high resolution and not
`a magnified view of a smaller area of the previously viewed
`image. In such case, the user would have to send further
`requests to the content provider to obtain an enlarged view
`of other areas of the previously viewed images not initially
`returned in response to the magnification request.
`Developing techniques for allowing users to better
`manipulate images is important given that the majority of
`data being downloaded over the Internet comprises image
`content and that in many instances users want to enlarge the
`view of an image. Thus, there is a need in the art to provide
`an improved method, system, and program for allowing a
`user to perform magnification operations on images down-
`loaded over the Internet and at the same time minimize
`
`network bandwidth usage and processing burdens imposed
`on the content provider server.
`SUMMARY OF THE PREFERRED
`EMBODIMENTS
`
`To overcome the limitations in the prior art described
`above, preferred embodiments disclose a system, method,
`and program for magnifying displayed content downloaded
`from a server over a network.
`Information is received
`
`indicating a selection of a region of the displayed content to
`magnify. A determination is made of at least one region of
`the selected region including image content. The server
`maintains a high resolution file version and a low resolution
`file version of the image content. A determination is then
`made as to whether the selected image content from the
`displayed image file is the low resolution file version. If so,
`a command is generated to retrieve from the server specific
`byte locations from the high resolution file version including
`the image content in the selected region. The specified bytes
`are less than all the image data bytes in the high resolution
`version of the file if the image content in the selected region
`comprises less than all of the image content maintained in
`the high resolution version of the file.
`In further embodiments, a requested magnification opera-
`tion is performed on the bytes in the high resolution file
`version retrieved from the server to magnify image content
`in the selected region.
`In yet further embodiments, a determination is made as to
`whether the selected region includes both text and image
`content. If so, a determination is made as to whether the text
`included in the selected region is in a vector graphics format.
`If so, a first magnification operation is performed on the
`bytes from the high resolution file version retrieved from the
`server to magnify the image content in the selected region.
`If there are text fonts in the selected region, then a second
`magnification operation is performed on the fonts in the
`vector graphic format by manipulating formulas that repre-
`sent the fonts to magnify the fonts in the selected region.
`Still further, if the fonts in the selected region are in a bit
`map format, a determination is made of a vector font
`corresponding to the bit map fonts. In such case, the second
`magnification operation is performed on the corresponding
`vector font.
`
`Preferred embodiments provide an improved method,
`system, and program for downloading image content from a
`
`

`

`US 6,700,589 B1
`
`3
`server when performing magnification operations on the
`image content. Preferred embodiments provide a technique
`that preserves image quality as the server provides a high
`resolution version of the image when the user or program
`selects to perform magnification of image content and
`because the fonts subject to magnification are in vector
`graphic format. Further, network bandwidth is preserved
`because only those high resolution bytes including image
`content that are in the selected region subject to the mag-
`nification are requested from the server, no more. Network
`bandwidth is also preserved because any magnification of
`text content
`that
`is in the selected region is performed
`locally, and no downloading is required. Moreover,
`the
`preferred magnification technique for image and text down-
`loaded from a server over a network reduces processing
`burdens on the server as the magnification operations are
`performed locally, not at the server.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Referring now to the drawings in which like reference
`numbers represents corresponding parts throughout:
`FIG. 1 illustrates a computing environment
`in which
`preferred embodiments are implemented; and
`FIGS. 2a, b illustrate logic implemented in a client
`magnification tool to magnify displayed pages including text
`and/or image content downloaded over a network.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`In the following description, reference is made to the
`accompanying drawings which form a part hereof, and
`which illustrate several embodiments of the present inven-
`tion. It is understood that other embodiments may be utilized
`and structural and operational changes may be made without
`departing from the scope of the present invention.
`
`Computing Environment
`
`in which
`FIG. 1 illustrates a computing environment
`preferred embodiments are implemented. The computing
`environment includes a user computer 2, which may com-
`prise any computer device known in the art, such as a
`desktop computer,
`laptop computer, workstation,
`mainframe, server, personal digital assistant (PDA), etc. The
`computer 2 includes a browser program 4, which may be any
`program capable of viewing text and images, such as a
`Hyptertext Mark-up Language (HTML) browser, e.g.,
`Microsoft Internet Explorer, Netscape Communicator,
`etc.** The computer 2 further includes a magnification tool
`6 to enlarge or reduce content displayed in the browser
`program 4. For instance,
`the magnification tool 6 could
`include the capabilities of the Zoom tool included with the
`Web Accessories for Microsoft Internet Explorer version 5,
`where the user may enlarge or reduce a image displayed in
`an HTML page.
`* *NETSCAPE is a registered trademark of the Netscape Communications
`Corporation; Microsoft is a registered trademark of the Microsoft Corporation
`The user computer 2 may communicate with a content
`server 10 over the Internet 12, or any other network, e.g., a
`LAN, Intranet, etc. The content server 10 is preferably a
`server class machine capable of managing numerous data
`requests from servers. The content server includes an HTTP
`server program 14 to respond to HTTP requests from
`browsers 4 in clients. The HTTP server 14 includes the
`
`capability to generate HTML pages including text and image
`content from a content database 16. Images in the content
`database 16 are maintained in a graphical file format known
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`4
`in the art, such as a bitmap, GIF, JPEG, etc. In preferred
`embodiments, the content database 16 maintains high reso-
`lution image files. The image files may comprise separate
`images or together may form a larger image, such as sections
`of a street map. In the case where a larger image is separated
`into multiple image files, an image index would be provided
`to associate one image file with a portion of the image.
`In preferred embodiments, when receiving a document
`request including an image component, the content server 10
`would return a low resolution version of the image. The
`content database 16 may maintain a low resolution version
`of each high resolution image. Alternatively,
`the content
`server 10 could generate a low resolution version of a
`requested high resolution image in the content database 16
`when assembling an HTML page in response to an HTTP
`request from the user computer 2.
`In preferred embodiments,
`the images included in the
`content database 16 would include specialized header infor-
`mation, along with other bit map header information known
`in the art, to allow the magnification tool 6 to take specific
`actions depending on the resolution of the image subject to
`a magnification operation. A bitmap image typically
`includes a bitmap file header, info header, table of color
`values and the bitmap data itself. The pixels of the image are
`stored by rows, left to right within each row, in a manner
`known in the art. The rows are stored bottom to top such that
`the first byte of a unit of pixel data is for the first pixel in the
`lower-left corner of the image. In preferred embodiments,
`information may be placed in the file header or info header
`indicating whether there is a corresponding high resolution
`image of the current bit map image and the resolution of the
`high resolution counterpart.
`FIGS. 2a, b illustrates logic implemented in the magni-
`fication tool 6 to process user requests to enlarge or reduce
`an area of an HTML page displayed in the browser 4. In
`preferred embodiments, the magnification tool 6 is incorpo-
`rated with the browser 4, such as a browser 4 plug-in, and
`is capable of controlling browser 4 operations, such as
`causing the browser 4 to generate an HTTP GET request to
`retrieve data from the content server 10 and manipulate the
`display of HTML pages downloaded from the Internet 12.
`The user computer 2 may download into the browser 4 an
`HTML page including text and images. The content provider
`may initially provide the user a low resolution version of an
`image in the requested HTML page to conserve network
`bandwidth and minimize download delay times. After down-
`loading the HTML page, the user may then, using an input
`device such as a mouse pointer, select within the browser 4
`a two-dimensional area to subject to magnification. In alter-
`native embodiments, the selection of magnification levels
`may occur automatically using predetermined magnification
`levels without requiring human interaction, such as during a
`self-running demo program. As used herein “magnification”
`refers to either enlargement or reduction of the content in a
`display region. The user’s invocation of the magnification
`tool 6 would initiate the operation at block 100 in FIG. 2A,
`where the magnification tool 6 receives coordinates of the
`user selection of an (x, y) area of the displayed HTML page
`and a user selected magnification operation to magnify the
`selected area according to a magnification factor.
`The magnification tool 6 determines whether the user
`selected area of the displayed page includes image content.
`If so, then control proceeds to block 104 in FIG. 2b, where
`the magnification tool 6 will read a predesignated area of the
`header fields of the image file including the selected image
`content
`to determine whether there is a high resolution
`counterpart to the displayed image. As discussed, in pre-
`
`

`

`US 6,700,589 B1
`
`5
`ferred embodiments, information is included in the image
`header fields to indicate whether there is a high resolution
`counterpart to the displayed image at the content server 10,
`including URL location information and the actual high
`resolution.
`
`If there is a high resolution version of the image, then at
`steps 108—114, the magnification tool 6 performs operations
`to determine the offsets into the pixel data area of the high
`resolution image of ranges of pixels that correspond to the
`user selected pixels in the low resolution image. Thus, for
`the pixels that form the user selected area of the low
`resolution image, the magnification tool 6 determines the
`corresponding pixels in the high resolution image that form
`the user selected area of the image. At block 108,
`the
`magnification tool 6 determines a pixel expansion ratio as
`the ratio of the number of pixels in the high resolution image
`to the number of pixels in the current displayed low reso-
`lution image. The magnification tool 6 then determines (at
`block 110) the byte offsets of the start and end of ranges of
`bytes that include the pixels of the user selected area in the
`low resolution image file. Each determined offset is then
`multiplied (at block 112) by the pixel expansion ratio to
`determine the start and end offsets of byte locations in the
`high resolution image file corresponding to the pixels in the
`user selected area of the low resolution image.
`The pixel data area of both the high and low resolution
`images would include the same number of bytes for the bit
`map file header, information, and color table fields. For this
`reason, the magnification tool 6 adds (at block 114) the byte
`length of these header fields to each determined offset byte
`in the pixel data area of the high resolution image to
`determine the byte offset of the start and end of each range
`of pixels in the selected image area from the beginning of the
`high resolution image file. The magnification tool 6 then
`generates an HTTP GET request to retrieve each range of
`bytes in the high resolution file including the user selected
`image area. The HTTP protocol allows a GET request to
`specify byte ranges of a file to download instead of the
`whole file. The magnification tool 6 may also cause the
`downloading of the header portions of the high resolution
`image to maintain information on those high resolution
`portions. Details of specifying a range header in the HTTP
`GET request are described in the Request for Comments
`2068 entitled “Hypertext Transfer Protocol—HTTP/1.1”
`(January 1997). The magnification tool 6 then has the
`browser 4 send the generated GET request including the
`specified byte ranges to the content server 10.
`After receiving (at block 120) the requested bytes of
`pixels from the high resolution image, the magnification tool
`6 performs (at block 122) the requested magnification on the
`high resolution pixel bytes to magnify the image portion of
`the user selected area using magnification techniques known
`in the art.
`
`If at block 104 the selected image area is already at the
`high resolution, i.e., there is no high resolution counterpart
`in the content server 10, then control proceeds to block 122
`to perform the requested magnification operation using the
`magnification factor and magnification techniques known in
`the art.
`
`After performing the magnification on the image portion
`of the user selected area of the HTML page or after deter-
`mining that there is no image portion included in the user
`selected area, then control transfers to block 124 in FIG. 2a
`determines whether the selected area of the HTML page
`includes text. If so, then the magnification tool 6 determines
`whether the text in the selected area is in a vector font
`
`format. Avector font comprises a geometrical/mathematical
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`definition and thus can be readily scaled without affecting
`the quality of the font. Abit map font is a font that is defined
`by a bit mapped representation of the font. Because a bit map
`font comprises a bit map of dots that forms the font, the
`quality of the bit map font would suffer if the bit map font
`is enlarged. For this reason, if the text comprises a bit map
`font, the magnification tool 6 maps (at block 128) the bit
`map font to a corresponding vector font, which can be scaled
`without reducing image quality. After the text is in a vector
`font format, the magnification tool 6 magnifies (at block
`130) the vector fonts in the text by the magnification factor
`to magnify the text.
`After all the text and image in the user selected area of the
`HTML page is magnified at blocks 122 and 130, control
`proceeds to block 132 to display the magnified text and/or
`image in the browser 4 display area.
`The preferred embodiment technique for magnifying a
`displayed region of a viewer, such as a browser,
`that
`downloads images from over a network such as the Internet
`minimizes download times by providing the user the mini-
`mal amount of data needed to magnify data in a manner that
`does not degrade the quality of the magnified image. The
`initial image presented, which is all the user may need, is in
`a low resolution format,
`thereby minimizing download
`times. If the user wants to magnify a portion of that low
`resolution image, then the preferred embodiment magnifi-
`cation tool will request the high resolution version of only
`those bytes of the selected magnification area. The user may
`then perform the magnification locally on the downloaded
`high resolution portion of the image. This differs from prior
`art techniques that overburden the content server by having
`the content server perform the magnification operations.
`Further, network bandwidth is conserved because only those
`high resolution bytes that are subject to the magnification are
`downloaded, not the image content in the entire displayed
`region.
`Still further, with preferred embodiments, different mag-
`nification operations are performed with respect to text to
`allow all magnification operations with respect to text to be
`performed locally. Yet further, text magnification operations
`preserve the image quality of the text by converting any bit
`map or scalar fonts to vector fonts before performing the
`magnification. This technique of performing separate mag-
`nification operations on text and images further conserves
`network bandwidth because any text portions of the selected
`area to magnify are not requested from the remote content
`server.
`
`Alternative Embodiments and Conclusions
`
`This concludes the description of the preferred embodi-
`ments of the invention. The following describes some alter-
`native embodiments for accomplishing the present inven-
`tion.
`
`The preferred embodiments may be implemented as a
`method, apparatus or article of manufacture using standard
`programming and/or engineering techniques to produce
`software, firmware, hardware, or any combination thereof.
`The term “article of manufacture” (or alternatively, “com-
`puter program product”) as used herein is intended to
`encompass one or more computer programs and/or data files
`accessible from one or more computer-readable devices,
`carriers, or media, such as magnetic storage media, “floppy
`disk,” CD-ROM, optical disks, holographic units, volatile or
`non-volatile electronic memory, etc. Further, the article of
`manufacture may comprise the implementation of the pre-
`ferred embodiments in a transmission media, such as a
`network transmission line, wireless transmission media,
`
`

`

`US 6,700,589 B1
`
`7
`infrared
`signals propagating through space, radio waves,
`signals, etc. Of course, those skilled in the art will recognize
`many modifications may be made to this configuration
`without departing from the scope of the present invention.
`Preferred embodiments were described with respect to
`presenting information in pages conforming to the HTML
`file format. However, the browser may be capable of dis-
`playing pages in formats other than HTML, such as a
`browser or viewer that is capable of displaying documents in
`a word processing format, graphic files or any other docu-
`ment format known in the art. In this way, the preferred
`embodiment magnification tool may be implemented with
`any document editing or viewing program that downloads
`documents from the Internet. In preferred embodiments, the
`browser or viewer with which the magnification tool inter-
`faces is capable of downloading pages from a remote server.
`In preferred embodiments,
`the magnification tool
`in
`which preferred embodiments are implemented is described
`as separate from the browser program.
`In alternative
`embodiments, the functionality of the preferred embodiment
`magnification tool may be incorporated into the browser
`program code.
`In preferred embodiments, the user computer and content
`server communicate over the Internet. However, in alterna-
`tive embodiments,
`the user and content server may be
`located within a local network, such as a LAN or Intranet.
`In preferred embodiments, the user computer requested
`documents using the HTTP protocol.
`In alternative
`embodiment, different communication protocols may be
`used to allow the user computer to request byte ranges from
`a document or image.
`In preferred embodiments, the magnification tool converts
`bitmap fonts to vector fonts before performing the magni-
`fication operations. In alternative embodiments, to magnify
`text components of combined text and image, the magnifi-
`cation tool may perform a bit map expansion of the bit map
`fonts.
`
`In preferred embodiments, the existence of a high reso-
`lution version of an image file of a displayed image is
`determined by examining information in the header fields of
`the displayed image. In alternative embodiments, the exist-
`ence of a high resolution version of an image file may be
`determined by querying the content server 14 for any high
`resolution versions of the image file including image content
`in the user selected area, without examining header infor-
`mation in the image file. This alternative embodiment does
`not require any specialized modifications to the header
`information in the bit map file, but does require further
`network communication, which may result
`in network
`delays to the requested operation.
`In summary,
`the present invention provides a system,
`method, and program for magnifying displayed content
`downloaded from a server over a network. Information is
`
`received indicating a selection of a region of the displayed
`content to magnify. A determination is made of at least one
`region of the selected region including image content. The
`server maintains a high resolution file version and a low
`resolution file version of the image content. Adetermination
`is then made as to whether the selected image content from
`the displayed image file is the low resolution file version. If
`so, a command is generated to retrieve from the server
`specific byte locations from the high resolution file version
`including the image content
`in the selected region. The
`specified bytes are less than all the image data bytes in the
`high resolution version of the file if the image content in the
`selected region comprises less than all of the image content
`maintained in the high resolution version of the file.
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`8
`The foregoing description of the preferred embodiments
`of the invention has been presented for the purposes of
`illustration and description. It is not intended to be exhaus-
`tive or to limit the invention to the precise form disclosed.
`Many modifications and variations are possible in light of
`the above teaching. It is intended that the scope of the
`invention be limited not by this detailed description, but
`rather by the claims appended hereto. The above
`specification, examples and data provide a complete descrip-
`tion of the manufacture and use of the composition of the
`invention. Since many embodiments of the invention can be
`made without departing from the spirit and scope of the
`invention,
`the invention resides in the claims hereinafter
`appended.
`What is claimed is:
`
`1. A method for magnifying displayed content down-
`loaded from a server over a network, comprising:
`receiving selection of a region of the displayed content to
`magnify;
`determining at least one region of the selected region
`including image content, wherein the server maintains
`a high resolution file version and a low resolution file
`version of the image content;
`determining whether the selected image content from the
`displayed image file is the low or high resolution file
`version;
`if the selected image is determined to be the low resolu-
`tion version of the file, then generating a command to
`retrieve from the server specific byte locations from the
`high resolution file version including the image content
`in the selected region, wherein the specified bytes are
`less than all the image data bytes in the high resolution
`version of the