Method and apparatus with preview image generation

1 . A processor-implemented method comprising:

determining identification information of a tile image corresponding to a visible region covered by a preview interface in a virtual image corresponding to an original image displayed on a screen of a user terminal, based on a zoom level received through the preview interface and a plurality of tile sets determined by downsampling the virtual image to different zoom levels;

determining image information of the tile image based on the identification information of the tile image; and

generating a preview image corresponding to the tile image by stitching the image information of the tile image.

2 . The method of claim 1 , wherein

the tile sets comprise identification information of tile images comprised in virtual images comprising different zoom levels through a pyramid structure, and

layers of the pyramid structure respectively correspond to the tile sets comprising the different zoom levels.

3 . The method of claim 1 , wherein the identification information of the tile image comprises any one or any combination of any two or more of a position of the tile image in the virtual image, a size of the tile image, and a flag indicating whether a plurality of tile sets comprises the tile image.

4 . The method of claim 1 , further comprising determining the virtual image as the same size as the size of the original image, based on a preset stitching setting.

5 . The method of claim 1 , further comprising determining a plurality of tile sets corresponding to different zoom levels by sampling the virtual image to the different zoom levels.

6 . The method of claim 1 , further comprising displaying the preview image on the preview interface.

7 . The method of claim 1 , further comprising either one or both of:

caching the tile image in a target tile set corresponding to a zoom level received through the preview interface among the tile sets; and

storing the target tile set in which the tile image is cached in a database.

8 . The method of claim 1 , further comprising:

determining whether the identification information of the tile image changes according to movement of the visible region; and

deleting a tile image corresponding to the changed identification information from a target tile set corresponding to the visible region in response to a change of the identification information of the tile image.

9 . A non-transitory computer-readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform the method of claim 1 .

10 . The method of claim 1 , wherein the determining the image information of the tile image comprises:

determining whether a plurality of tile sets comprises the tile image, based on the identification information of the tile image;

determining the image information of the tile image from the tile sets in response to determining that the tile sets comprise the tile image; and

updating the tile image in response to determining that the tile sets do not comprise the tile image.

11 . The method device of claim 10 , wherein the updating the tile image comprises:

updating the tile image corresponding to the visible region in response to determining that the tile sets do not comprise an entirety of the tile image; and

updating a tile image corresponding to a peripheral region of the visible region in response to determining that the tile sets comprise the entirety of the tile image.

12 . The method of claim 11 , wherein the updating the tile image corresponding to the visible region comprises:

determining target identification information of the tile image comprised in a target tile set covered by the visible region of the tile sets;

determining partial images for stitching in the original image by performing reverse mapping on the original image, based on the target identification information; and

partially updating the tile image corresponding to the visible region by partially stitching the partial images to a portion of the tile image.

13 . The method of claim 11 , wherein the updating the tile image corresponding to the visible region comprises:

determining whether a database comprises the tile image that is not comprised in the tile sets;

extracting the tile image that is not comprised in the tile sets from the database in response to determining that the database comprises the tile image that is not comprised in the tile sets; and

storing the extracted tile image in a target tile set corresponding to the visible region.

14 . The method of claim 11 , wherein the updating the tile image corresponding to the visible region comprises:

determining whether the identification information of the tile image changes according to movement of the visible region; and

updating a tile image corresponding to a new region covered by the moved visible region in the tile sets corresponding to different zoom levels in response to determining that the identification information of the tile image changes.

15 . The method of claim 14 , wherein the updating the tile image corresponding to the new region comprises:

determining whether a portion of a tile image covered by the preview interface in the moved visible region changes; and

removing a tile image that is not covered by the preview interface from a target tile set corresponding to a zoom level received by a user in response to determining that the portion of the tile image covered by the preview interface changes.

16 . A processor-implemented method comprising:

determining identification information of a tile image corresponding to a visible region covered by a preview interface in a virtual image corresponding to an original image displayed on a screen of a user terminal;

determining image information of the tile image based on the identification information of the tile image; and

generating a preview image corresponding to the tile image by stitching the image information of the tile image,

wherein the determining the identification information of the tile image comprises determining the identification information of the tile image, based on a zoom level received through the preview interface and a plurality of tile sets determined by downsampling the virtual image to different zoom levels, and

wherein the received zoom level is determined by a user gesture that is recognized through the preview interface on the screen of the user terminal.

17 . The method of claim 16 , wherein the user gesture comprises any one or any combination of any two or more of zoom-in and zoom-out operations performed using two fingers of a user, zoom-in and zoom-out operations performed through a double click of the user, and a dragging operation performed by the user.

18 . An apparatus comprising:

one or more processors;

a memory comprising one or more non-transitory storage media that store instructions that, when executed by the one or more processors, configures the electronic device to:

determine identification information of a tile image corresponding to a visible region covered by a preview interface in a virtual image corresponding to an original image displayed on a screen of a user terminal, based on a zoom level received through the preview interface and a plurality of tile sets determined by downsampling the virtual image to different zoom levels;

determine image information of the tile image based on the identification information of the tile image; and

generate a preview image corresponding to the tile image by stitching the image information of the tile image.

19 . The apparatus of claim 18 , further comprising a display device configured to display the preview image through the preview interface.