1. A method comprising: outputting, by a computing device that includes one or more processors, for display, a plurality of characters; receiving, by the computing device, an input indicative of a slide gesture across one or more regions of a presence-sensitive input device, the one or more regions being associated with a group of characters included in the plurality of characters; determining, by the computing device and based at least in part on one or more of an origination point and a speed of movement associated with the slide gesture, whether the slide gesture represents a character string-level selection or a character-level selection from the group of characters, wherein the character string-level selection comprises a multi-character selection of a character string from the group of characters; responsive to determining that the slide gesture represents the character string-level selection from the group of characters and determining that the input indicative of the slide gesture covers only a portion of at least one character string included in the group of characters, outputting, by the computing device and for display, a graphical selection of the at least one character string, such that the at least one character string is visually differentiated from any of the plurality of characters not included in the group of characters, wherein the at least one character string comprises two or more consecutive characters included in the group of characters, and wherein the at least one character string does not comprise any space characters; and responsive to determining that the slide gesture represents the character-level selection from the group of characters, outputting, by the computing device, for display and in single character increments, a graphical selection of at least one character included in the group of characters, such that the at least one character is visually differentiated from any of the plurality of characters not included in the group of characters: and outputting, for display and in a preview area of a user interface (UI), one or more occluded characters of the plurality of characters, wherein the plurality of characters is displayed at a display area of the UI, wherein the computing device detects a user contact at a region of the presence-sensitive input device that is associated with the one or more occluded characters, and wherein the preview area of the UI is different from the display area of the UI.