Difference between revisions of "Legacy:Canvas (UT)"

Latest revision as of 19:38, 4 November 2015

The Canvas is a wrapper for methods for drawing text, textures and meshes on the local player's screen. Canvas objects are passed to various events and functions in the following classes:

See Canvas for Canvas properties and methods available in UT2003.

Sobiwan: I looked for the function PostRender() in the the above classes and every one of them calls PostRender (canvas Canvas). Since functions can pass a class type and a name, is the syntax for this case PostRender (type name)? Is it saying "run the postrender function on the class type canvas on the class name Canvas"? I dont understand why not just pass the type (canvas) since that is its name.

RDGDanClark: The function needs to know the type of variable that you're passing it, in all cases. What they've done here is a pretty good example of bad programming style. Just as you should never have a variable in your code of type int called Int or of type float called Float, you should never have a variable of type canvas called Canvas. You're right about the translation though, it is saying "run the PostRender function using a passed variable of type canvas that is called Canvas".

Properties[edit]

float ClipX, ClipY 

Bottom right clipping region.

float CurX, CurY 

Current position for drawing.

float OrgX, OrgY 

Origin for drawing.

float SpaceX, SpaceY 

Spacing for after Draw.

float SizeX, SizeY (const) 

Zero-based actual dimensions.

float CurYL 

Largest Y size since DrawText.

byte Style 

The values of this variable correspond to the ERenderStyle enum of the Actor (UT) class, but that can't be used in this class.

bool bCenter 

Whether to center the text.

bool bNoSmooth 

Whether bilinear filtering should not be applied.

color DrawColor 

Color to use for drawing. White (R=255,G=255,B=255) means draw everything in its default colors. If any color component is lower than 255 the specific color component of the Texture (UT) or Font will be drawn darker. (or more translucent, see color blending)

Font Font 

Font for DrawText.

Font SmallFont, MedFont, BigFont, LargeFont 

system fonts with different sizes.

Viewport ViewPort (const) 

Viewport that owns the canvas.

float Z 

Z location. 1=no screenflash, 2=yes screenflash.

Methods[edit]

Texture Drawing[edit]

DrawTile (Texture (UT) Tex, float XL, float YL, float U, float V, float UL, float VL) 

This draws a rectangle within the texture onto the screen. The upper left of the texture will be at the current pen position.

• Tex - the texture to draw.
• XL, YL - width and height on the screen, in number of pixels.
• U, V - coordinates, within the texture, of the upper left of the rectangular window.
• UL, VL - width and height, in pixels, of the window within the texture.

DrawTileClipped (Texture (UT) Tex, float XL, float YL, float U, float V, float UL, float VL) 

DrawPattern (Texture (UT) Tex, float XL, float YL, float Scale) 

This draws the specifed texture onto the screen, tiling it to fit a rectangle. The upper left of the rectangle will be at the current pen position.

• Tex - the texture to draw.
• XL, YL - width and height of the rectangle.
• Scale - scale the texture (proportionately) by this ratio.

Draconx: There are some bizarre things I've noticed with this function. Try using it to draw onto a UWindow, then move that UWindow around to see an interesting effect. I will have to investigate exactly what this function does later. For drawing tiled backgrounds on UWindows, the DrawTile() function (defined in UWindowWindow) seems to work much better.

DrawIcon (Texture (UT) Tex, float Scale) 

This draws and proportionately scales the specified texture onto the screen. The upper left of the texture will be at the current pen position.

• Tex - the texture to draw.
• Scale - scale the texture by this ratio.

DrawRect (Texture (UT) Tex, float RectX, float RectY) 

This draws and disproportionately scales the specified texture onto the screen. The upper left of the texture will be at the current pen position.

• Tex - the texture to draw.
• RectX - the new width of the texture
• RectY - the new height of the texture

Text Drawing[edit]

StrLen (coerce string String, out float XL, out float YL) 

Get the size of a string when it would be drawn by DrawText() using the current font.

DrawText (coerce string Text, optional bool CR) 

DrawTextClipped (coerce string Text, optional bool bCheckHotKey) 

TextSize (coerce string String, out float XL, out float YL) 

Get the size of a string when it would be drawn by DrawTextClipped() using the current font.

Actor Drawing[edit]

DrawActor (Actor (UT) A, bool WireFrame, optional bool ClearZ) 

Draws the actor A at its current location, whether it's actually visible or not. The actor can be drawn as wire frame or how it actually looks. ClearZ causes the actor to be drawn on top of everything else, i.e. it will be visible even if it would normally be (partially or completely) obscured by other objects.

DrawClippedActor (Actor (UT) A, bool WireFrame, int X, int Y, int XB, int YB, optional bool ClearZ) 

Same as DrawActor(), but only draws within the rectangle specified by X, Y, XB and YB.

Misc Stuff[edit]

DrawPortal (int X, int Y, int Width, int Height, Actor (UT) CamActor, vector CamLocation, rotator CamRotation, optional int FOV, optional bool ClearZ) 

Note: This doesn't draw sprites (this includes particles and coronas) correctly in UT.

Reset ( ) 

Resets the canvas properties.

SetPos (float X, float Y) 

Sets the drawing position.

SetOrigin (float X, float Y) 

Sets the origin of the canvas by changing the OrgX and OrgY properties.

SetClip (float X, float Y) 

Sets the clipping size of the canvas by changing the ClipX and ClipY properties.