MICROSOFT_PRESS_EBOOK_PROGRAMMING_WINDOWS_8_APPS_WITH_HTML_CSS_AND_JAVASCRIPT_PDF

You might notice in the table above that many of the gestures in the touch language don’t actually
have a single event associated with them (like pinch or rotate) but are instead represented by a series of
gesture or pointer events. The reason for this is that these gestures, when used with touch, typically
involve animation of the affected content while the gesture is happening. Swipes, for example, show
linear movement of the object being panned or selected. A pinch or stretch movement will often be
actively zooming the content. (Semantic Zoom is an exception, but then you just let the control handle
the details.) And a rotate gesture should definitely give visual feedback. In short, handling these
gestures with touch, in particular, means dealing with a series of events rather than just a single one.
This is one reason that it’s so helpful (and time-saving!) to use the built-in controls as much as
possible, because they already handle all the gesture details for you. The ListView control, for example,
contains all the pointer/gesture logic to handling pans and swipes, along with taps. The Semantic Zoom
control, like I said, implements pinch and stretch by watching MSPointer* events. If you look at the
source code for these controls within WinJS, you’ll start to appreciate just how much they do for you
(and what it will look like to implement a rich custom control of your own, using the gesture
recognizer!).
You can also save yourself a lot of trouble with the -ms-touch-action CSS properties described under
“CSS Styles That Affect Input.” Using this has the added benefit of processing the touch input on a
non-UI thread, thereby providing much smoother manipulation than could be achieved by handling
pointer or gesture events.
On the theme of “write for touch and get other input for free,” all of these gestures also have mouse
and keyboard equivalents, which the built-in controls also implement for you. It’s also helpful to know
what those equivalents are, as shown in the table below. The “Standard Keystrokes” section later in this
chapter also lists many other command-related keystrokes.
Touch Keyboard Mouse Pen/Stylus
Press and hold (or Right-click button Right button click Press and hold
tap on text selection)
Tap Enter Left button click Tap
Slide (short distance) Arrow keys Left button click and drag, click on
scrollbar arrows, drag the scrollbar
thumb, use the mouse wheel
Slide + inertia
(long distance)
Page Up/Page Down
Left button click and drag, click on
scrollbar track, drag the scrollbar
thumb, use the mouse wheel
Swipe to select Right-click button or spacebar Right button click Tap and drag
Tap on scrollbar arrows, drag
scrollbar thumb, tap and drag
Tap on scrollbar track, drag
scrollbar thumb, tap and drag
Pinch/Stretch Ctrl+ and Ctrl- Ctrl+mouse wheel or UI command UI command or other
hardware feature
Swipe from edge
Win+Z, Win+Tab, Win+C or
Win+Shift+C
Clicking on corners of the screen;
right-click shows app bar
Drag in from edge
Rotate Ctrl+, and Ctrl+. Ctrl+Shift+mouse wheel UI command or other
hardware feature
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