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PhDragEvent_t

Data associated with a drag event

Synopsis:

typedef struct Ph_ev_drag_data {
    PhRect_t            rect;
    PhRid_t             rid;
    PhRect_t            boundary;
    PhDim_t             min;
    PhDim_t             max;
    PhDim_t             step;
    unsigned long       key_mods;
    long                zero[2];
    ushort_t            flags;
} PhDragEvent_t;

Description:

The PhDragEvent_t structure defines the data associated with Ph_EV_DRAG events (see PhEvent_t). It contains at least the following members:

rect

A PhRect_t structure that contains the coordinates of the initial, current, or final drag rectangle, depending on the drag-event subtype value.

rid

The ID of the region that initiated the drag operation. Your application needs to specify the region ID when it calls PhInitDrag() to initiate the dragging operation.

boundary

A PhRect_t structure that contains the coordinates of the rectangle that constrains the drag operation.

min, max

PhDim_t structures that define the minimum and maximum sizes of the drag rectangle, as specified in the call to PhInitDrag().

step

A PhDim_t structure that defines the drag operation's granularity, as specified in the call to PhInitDrag().

key_mods

Your application can use the modifier keys (e.g. Shift or Num Lock) to change the meaning of a drag event. When a modifier key is pressed or released, it's evaluated through a table, and the key_mods field is updated accordingly. This evaluation is done before the drag event is sent.

The key_mods member is a combination of the following bits:

• Pk_KM_Shift
• Pk_KM_Ctrl
• Pk_KM_Alt
• Pk_KM_AltGr
• Pk_KM_Shl3
• Pk_KM_Mod6
• Pk_KM_Mod7
• Pk_KM_Mod8
• Pk_KM_Shift_Lock
• Pk_KM_Ctrl_Lock
• Pk_KM_Alt_Lock
• Pk_KM_AltGr_Lock
• Pk_KM_Shl3_Lock
• Pk_KM_Mod6_Lock
• Pk_KM_Mod7_Lock
• Pk_KM_Mod8_Lock
• Pk_KM_Caps_Lock
• Pk_KM_Num_Lock
• Pk_KM_Scroll_Lock

If the Shift key is pressed, the Shift modifier is on; if it's released, the Shift modifier is off. Because some keys occur twice on the keyboard, a key release doesn't guarantee that the corresponding modifier is off -- the matching key may still be pressed.

unsigned short flags

Flags that indicate which edges of the drag rectangle track the pointer. You can OR the following values into flags:

• Ph_DRAG_NOBUTTON -- Allow the drag to start, even if the user isn't holding down a button.
• Ph_DRAG_KEY_MOTION -- During the drag, emit drag events with the Ph_EV_DRAG_KEY_EVENT or the Ph_EV_DRAG_MOTION_EVENT subtype (see PhEvent_t).
• Ph_DRAG_TRACK -- No drag outline is drawn, and Ph_EV_DRAG_MOVE events are emitted to the initiating region. Use this flag if you want to implement your own visual interpretation of dragging operations.
• Ph_TRACK_LEFT -- left edge tracks the pointer.
• Ph_TRACK_RIGHT -- right edge tracks the pointer.
• Ph_TRACK_TOP -- top edge tracks the pointer.
• Ph_TRACK_BOTTOM -- bottom edge tracks the pointer.
• Ph_TRACK_DRAG -- all edges track the pointer (the same as using all four of the above values).

Classification:

Photon

See also:

PhDim_t, PhEvent_t, PhInitDrag(), PhPoint_t, PhRect_t

"Dragging" in the Events chapter of the Photon Programmer's Guide