- 0 2.0
Displays the pen data in an HPENDATA
object as a trail of visible ink.
DrawPenData( HDC hdc, LPRECT lprect, HPENDATA hpndt )
Handle to a device context. This parameter can also be the handle of a
Bounding rectangle of ink, in client coordinates. Can be NULL.
Handle to a pen data object.
This function does not return a value. If hpndt
is NULL, DrawPenData
DrawPenData draws the pen data in the specified device context using the GDI Polyline
function. The current settings in the device context rather than the ink
characteristics determine how the data is rendered. This means the ink width and
color specified in the PENDATAHEADER
structure have no effect on how DrawPenData
renders the ink. To alter the display characteristics of the ink, an
application must call the appropriate Windows GDI functions to set the GDI drawing pen
(not to be confused with the real pen).
The application using DrawPenData
must either scale the data points or set the mapping appropriately if lprect
is not NULL, the points are scaled into lprect
as the drawing is done. Internally, nondestructive calls to the SetViewportExtEx
, and SetWindowExtEx
functions are used to render the pen data in the device context within the
bounds of the provided rectangle. An application must compute the proper pen
width (if it is other than 1) before calling this function with a valid lprect
parameter to account for the scaling that occurs.
draws the ink in the rectangle relative to the upper-left corner of the
window. It ignores any changes that have been made to the origin of the device
context by previous calls to the SetWindowOrg
functions. If the origin has changed, the rectangle passed to DrawPenData
must be offset by the appropriate amount.
If the ink is to be drawn with a width of greater than 1 pixel, the width of
the currently selected pen must be set to achieve the desired result. The width
must be set in client coordinates if a mapping mode is set in the device
context. For example, if the mapping mode has been set to MM_HIENGLISH, the pen width
must be set to a number appropriate for the desired width in MM_HIENGLISH
units to preserve the proper scale of the ink. This scaling is only an issue when
the ink width is greater than 1.
The rendering of the ink data produced by DrawPenData
generally does not exactly match the rendering produced by the display driver
when the data was first collected. This discrepancy results because DrawPenData
and the Polyline
function use different algorithms to draw the data. The difference is an
occasional "off by one" error that appears as a shifting of some pixels around the
edges, depending on the rounding done by Polyline
. An application that requires an exact replication of the original ink
rendering should call the RedisplayPenData
function allows more control when drawing the contents of pen structures.
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