ID Number: Q27585
1.03 2.03 2.10 3.00 3.10
WINDOWS
Summary:
Windows GDI functions, such as Rectangle, Ellipse, RoundRect,
Chord, and Pie, have parameters that specify the coordinates of a
"bounding box" into which the figure is drawn. Windows draws the
figure up to, but not including, the right and bottom coordinates.
More Information:
Suppose the following call is made:
Rectangle(hDC, 1, 1, 5, 3)
Assuming that the device context is using the MM_TEXT mapping mode (in
which case logical units map directly to physical pixels), the
resulting rectangle will be 4 pixels wide and 2 pixels tall. The
following diagram shows which pixels are affected:
---0-----1-----2-----3-----4-----5-----6-
| | | | | | |
0 | | | | | |
|-----|-----|-----|-----|-----|-----|----
| | | | | | |
1 | X | X | X | X | |
|-----|-----|-----|-----|-----|-----|----
| | | | | | |
2 | X | X | X | X | |
|-----|-----|-----|-----|-----|-----|----
| | | | | | |
3 | | | | | |
|-----|-----|-----|-----|-----|-----|----
| | | | | | |
4 | | | | | |
It may be helpful to think of the display as a grid, with each pixel
contained in a grid cell. The X1, Y1, X2, and Y2 parameters to the
Rectangle function specify an imaginary "bounding box" drawn on the
grid. The rectangle is drawn within the bounding box.
The height, width, and area of the resulting rectangle have the
following useful properties:
Height = X2 - X1
Width = Y2 - Y1
Area = Height * Width
Additional reference words: 1.03 1.x 2.03 2.10 2.x 3.00 3.10 3.x
TAR73067