# DrawableRegion¶

class DrawableRegion

This is a base class for GraphicsWindow (actually, GraphicsOutput) and DisplayRegion, both of which are conceptually rectangular regions into which drawing commands may be issued. Sometimes you want to deal with a single display region, and sometimes you want to deal with the whole window at once, particularly for issuing clear commands and capturing screenshots.

Inheritance diagram

enum RenderTexturePlane

It seems awkward to have this type, and also RenderBuffer::Type. However, the fact that RenderBuffer::Type is a bitmask makes it awfully awkward to work with.

enumerator RTP_stencil = 0
enumerator RTP_depth_stencil = 1
enumerator RTP_color = 2
enumerator RTP_aux_rgba_0 = 3
enumerator RTP_aux_rgba_1 = 4
enumerator RTP_aux_rgba_2 = 5
enumerator RTP_aux_rgba_3 = 6
enumerator RTP_aux_hrgba_0 = 7
enumerator RTP_aux_hrgba_1 = 8
enumerator RTP_aux_hrgba_2 = 9
enumerator RTP_aux_hrgba_3 = 10
enumerator RTP_aux_float_0 = 11
enumerator RTP_aux_float_1 = 12
enumerator RTP_aux_float_2 = 13
enumerator RTP_aux_float_3 = 14
enumerator RTP_depth = 15
enumerator RTP_COUNT = 16
virtual void disable_clears(void)

Disables both the color and depth clear. See set_clear_color_active() and set_clear_depth_active().

virtual bool get_clear_active(int n) const

Gets the clear-active flag for any bitplane.

LColor const &get_clear_color(void) const

Returns the current clear color value. This is the value that will be used to clear the color buffer every frame, but only if get_clear_color_active() returns true. If get_clear_color_active() returns false, this is meaningless.

bool get_clear_color_active(void) const

Returns the current setting of the flag that indicates whether the color buffer should be cleared every frame. See set_clear_color_active().

PN_stdfloat get_clear_depth(void) const

Returns the current clear depth value. This is the value that will be used to clear the depth buffer every frame, but only if get_clear_depth_active() returns true. If get_clear_depth_active() returns false, this is meaningless.

bool get_clear_depth_active(void) const

Returns the current setting of the flag that indicates whether the depth buffer should be cleared every frame. See set_clear_depth_active().

unsigned int get_clear_stencil(void) const

Returns the current clear stencil value. This is the value that will be used to clear the stencil buffer every frame, but only if get_clear_stencil_active() returns true. If get_clear_stencil_active() returns false, this is meaningless.

bool get_clear_stencil_active(void) const

Returns the current setting of the flag that indicates whether the color buffer should be cleared every frame. See set_clear_stencil_active().

virtual LColor const &get_clear_value(int n) const

Returns the clear value for any bitplane.

PN_stdfloat get_pixel_factor(void) const

Returns the amount by which the height and width of the region will be scaled internally, based on the zoom factor set by set_pixel_zoom(). This will return 1.0 if the pixel_zoom was not set or if it is not being respected (for instance, because the underlying renderer doesn’t support it –see supports_pixel_zoom()).

PN_stdfloat get_pixel_zoom(void) const

Returns the value set by set_pixel_zoom(), regardless of whether it is being respected or not. Also see get_pixel_factor().

static int get_renderbuffer_type(int plane)

Returns the RenderBuffer::Type that corresponds to a RenderTexturePlane.

virtual bool is_any_clear_active(void) const

Returns true if any of the clear types (so far there are just color or depth) have been set active, or false if none of them are active and there is no need to clear.

virtual void set_clear_active(int n, bool clear_aux_active)

Sets the clear-active flag for any bitplane.

void set_clear_color(LColor const &color)

Sets the clear color to the indicated value. This is the value that will be used to clear the color buffer every frame, but only if get_clear_color_active() returns true. If get_clear_color_active() returns false, this is meaningless.

void set_clear_color_active(bool clear_color_active)

Toggles the flag that indicates whether the color buffer should be cleared every frame. If this is true, the color buffer will be cleared to the color indicated by set_clear_color(); otherwise, it will be left alone.

void set_clear_depth(PN_stdfloat depth)

Sets the clear depth to the indicated value. This is the value that will be used to clear the depth buffer every frame, but only if get_clear_depth_active() returns true. If get_clear_depth_active() returns false, this is meaningless.

void set_clear_depth_active(bool clear_depth_active)

Toggles the flag that indicates whether the depth buffer should be cleared every frame. If this is true, the depth buffer will be cleared to the depth value indicated by set_clear_depth(); otherwise, it will be left alone.

void set_clear_stencil(unsigned int stencil)

Sets the clear stencil to the indicated value. This is the value that will be used to clear the stencil buffer every frame, but only if get_clear_color_active() returns true. If get_clear_stencil_active() returns false, this is meaningless.

void set_clear_stencil_active(bool clear_stencil_active)

Toggles the flag that indicates whether the stencil buffer should be cleared every frame. If this is true, the stencil buffer will be cleared to the value indicated by set_clear_stencil(); otherwise, it will be left alone.

virtual void set_clear_value(int n, LColor const &clear_value)

Sets the clear value for any bitplane.

virtual void set_pixel_zoom(PN_stdfloat pixel_zoom)

Sets the amount by which the pixels of the region are scaled internally when filling the image interally. Setting this number larger makes the pixels blockier, but may make the rendering faster, particularly for software renderers. Setting this number to 2.0 reduces the number of pixels that have to be filled by the renderer by a factor of 2.0. It doesn’t make sense to set this lower than 1.0.

It is possible to set this on either individual DisplayRegions or on overall GraphicsWindows, but you will get better performance for setting it on the window rather than its individual DisplayRegions. Also, you may not set it on a DisplayRegion that doesn’t have both clear_color() and clear_depth() enabled.

This property is only supported on renderers for which it is particularly useful–currently, this is the tinydisplay software renderer. Other kinds of renderers allow you to set this property, but ignore it.

virtual bool supports_pixel_zoom(void) const

Returns true if a call to set_pixel_zoom() will be respected, false if it will be ignored. If this returns false, then get_pixel_factor() will always return 1.0, regardless of what value you specify for set_pixel_zoom().

This may return false if the underlying renderer doesn’t support pixel zooming, or if you have called this on a DisplayRegion that doesn’t have both set_clear_color() and set_clear_depth() enabled.