Image placement

Macros
#define	oslSetImageTile(img, x0, y0, x1, y1)
	Sets the source rectangle of the image to be displayed.
#define	oslSetImageTileSize(img, x0, y0, x1, y1)
	Sets the source rectangle of the image to be displayed using tile size.
#define	oslResetImageTile(img)
	Resets the image rectangle to its full (original) size.
#define	oslMirrorImageH(img)
	Mirrors an image (or an image tile) horizontally.
#define	oslMirrorImageV(img)
	Mirrors an image (or an image tile) vertically.
#define	oslImageIsMirroredH(img)
	Returns whether the image is mirrored horizontally.
#define	oslImageIsMirroredV(img)
	Returns whether the image is mirrored vertically.
#define	oslImageRotMoveX(img, x)
	Calculates the x-coordinate for moving an image so that its top-left corner is at the specified position when no rotation is applied.
#define	oslImageRotMoveY(img, y)
	Calculates the y-coordinate for moving an image so that its top-left corner is at the specified position when no rotation is applied.
#define	oslSetImageRotCenter(img)
	Sets the rotation center of an image to its center.
#define	oslImageSetRotCenter   oslSetImageRotCenter
	Alias for oslSetImageRotCenter.
#define	oslCorrectImageHalfBorder(img)
	Crops 0.5 pixel from each corner of the image.
#define	oslResetImageHalfBorder(img)
	Undoes the effect of oslCorrectImageHalfBorder.
#define	oslGetImageWidth(img)
	Returns the width of the image, considering the current frame or tile.
#define	oslGetImageHeight(img)
	Returns the height of the image, considering the current frame or tile.
#define	oslGetImageSizeX   oslGetImageWidth
	Returns the width of the image, considering the current frame or tile.
#define	oslGetImageSizeY   oslGetImageHeight
	Returns the height of the image, considering the current frame or tile.

Detailed Description

Image placement in OSLib.

Macro Definition Documentation

oslSetImageTile

#define oslSetImageTile	(		img,
			x0,
			y0,
			x1,
			y1 )

Value:

({ (img)->offsetX0=(float)x0, (img)->offsetY0=(float)y0, (img)->offsetX1=(float)x1, (img)->offsetY1=(float)y1; (img)->stretchX = oslAbs((int)((float)((img)->offsetX1) - (float)((img)->offsetX0))), (img)->stretchY = oslAbs((int)((float)((img)->offsetY1) - (float)((img)->offsetY0))); })

Sets the source rectangle of the image to be displayed.

This macro allows you to define a sub-region of a larger image to be rendered. This is useful when you have an image that contains multiple sprites or tiles arranged in a grid.

For example, if you have a 128x128 image containing 16 sprites of 32x32 each, you can use this macro to select and display a specific sprite:

oslSetImageTile(image, 0, 0, 32, 32);
oslDrawImage(image);

This will display the portion of the image starting at (0,0) and ending at (32,32), rendering a 32x32 sprite. To display the next sprite to the right, you would use:

oslSetImageTile(image, 32, 0, 64, 32);

Parameters

img	The image from which a tile is to be extracted.
x0	The x-coordinate of the top-left corner of the tile.
y0	The y-coordinate of the top-left corner of the tile.
x1	The x-coordinate of the bottom-right corner of the tile (exclusive).
y1	The y-coordinate of the bottom-right corner of the tile (exclusive).

Note

The specified coordinates are used to define the source rectangle within the image. The image will be drawn with the specified tile dimensions.

See also

Refer to oslDrawImage for rendering the Images with the selected tile.

oslSetImageTileSize

#define oslSetImageTileSize	(		img,
			x0,
			y0,
			x1,
			y1 )

Value:

({ (img)->offsetX0 = (float)(x0), (img)->offsetY0 = (float)(y0), (img)->offsetX1 = (float)(x0) + (float)(x1), (img)->offsetY1 = (float)(y0) + (float)(y1), (img)->stretchX = (int)(x1), (img)->stretchY = (int)(y1); })

Sets the source rectangle of the image to be displayed using tile size.

This macro allows you to define a sub-region of a larger image to be rendered by specifying the size of the tile directly. This simplifies the process of defining a tile or sprite within an image.

For example, if you have a 128x128 image containing 32x32 sprites, you can use this macro to select and display a specific sprite by setting the size of the tile:

oslSetImageTileSize(image, 0, 0, 32, 32);
oslDrawImage(image);

This will display a 32x32 tile starting from (0,0) and ending at (32,32). To display a sprite starting at (32,0) with the same size, you would use:

oslSetImageTileSize(image, 32, 0, 32, 32);

Parameters

img	The image from which a tile is to be extracted.
x0	The x-coordinate of the top-left corner of the tile.
y0	The y-coordinate of the top-left corner of the tile.
x1	The width of the tile.
y1	The height of the tile.

Note

The specified coordinates define the starting position and size of the tile within the image. The image will be drawn with the specified tile dimensions.

See also

Refer to oslDrawImage for rendering the Images with the selected tile.

oslResetImageTile

#define oslResetImageTile

(

img

)

Value:

({ (img)->offsetX0=0, (img)->offsetY0=0, (img)->offsetX1=(img)->sizeX, (img)->offsetY1=(img)->sizeY; (img)->stretchX = (img)->sizeX, (img)->stretchY = (img)->sizeY; })

Resets the image rectangle to its full (original) size.

This macro resets the portion of the image to be drawn to cover the entire image. It effectively cancels any previous tile or sub-region settings, allowing you to draw the full image again.

For example, if you previously set a specific tile or sub-region of the image using oslSetImageTile or oslSetImageTileSize, you can use this macro to revert to displaying the entire image.

oslSetImageTile(image, 0, 0, 32, 32);
oslDrawImage(image);
// Reset to full image
oslResetImageTile(image);
oslDrawImage(image);

Parameters

img	The image whose rectangle is to be reset.

Note

After calling this macro, the image will be rendered using its full dimensions (sizeX and sizeY), effectively ignoring any previously set tile or sub-region settings.

See also

Refer to oslSetImageTile and oslSetImageTileSize for setting specific sub-regions of an Images.

oslMirrorImageH

#define oslMirrorImageH

(

img

)

Value:

({ float ___tmp;  ___tmp = (img)->offsetX0; (img)->offsetX0 = (img)->offsetX1; (img)->offsetX1 = ___tmp; })

Mirrors an image (or an image tile) horizontally.

This macro flips the image horizontally by swapping the offsetX0 and offsetX1 coordinates of the image. It effectively mirrors the image along the vertical axis. If this macro is used in a loop or multiple times, make sure to reset the mirroring after drawing the image to avoid undesired effects, as each application of this macro will mirror the image again.

For example, if you want to mirror an image horizontally and then reset it to its original orientation, you might use:

oslMirrorImageH(image);
oslDrawImage(image);
oslResetImageTile(image); // Reset after drawing

Parameters

img	The image to be mirrored.

Note

Mirroring an image twice will revert it to its original orientation. If you are applying mirroring in a loop, ensure to reset the mirroring state after drawing to maintain correct orientation.

See also

Use oslMirrorImageV to mirror an Images vertically.

oslMirrorImageV

#define oslMirrorImageV

(

img

)

Value:

({ float ___tmp;  ___tmp = (img)->offsetY0; (img)->offsetY0 = (img)->offsetY1; (img)->offsetY1 = ___tmp; })

Mirrors an image (or an image tile) vertically.

This macro flips the image vertically by swapping the offsetY0 and offsetY1 coordinates of the image. It effectively mirrors the image along the horizontal axis. If this macro is used in a loop or multiple times, make sure to reset the mirroring after drawing the image to avoid undesired effects, as each application of this macro will mirror the image again.

For example, if you want to mirror an image vertically and then reset it to its original orientation, you might use:

oslMirrorImageV(image);
oslDrawImage(image);
oslResetImageTile(image); // Reset after drawing

Parameters

img	The image to be mirrored.

Note

Mirroring an image twice will revert it to its original orientation. If you are applying mirroring in a loop, ensure to reset the mirroring state after drawing to maintain correct orientation.

See also

Use oslMirrorImageH to mirror an Images horizontally.

oslImageIsMirroredH

#define oslImageIsMirroredH

(

img

)

Value:

((img)->offsetX1 > (img)->offsetX0)

Returns whether the image is mirrored horizontally.

This macro checks if the image has been mirrored horizontally. An image is considered to be mirrored horizontally if the x-coordinate of the bottom-right corner (offsetX1) is greater than the x-coordinate of the top-left corner (offsetX0).

Parameters

img	The image to check for horizontal mirroring.

Returns

Returns true if the image was mirrored horizontally, false otherwise.

See also

Use oslMirrorImageH to mirror the Images horizontally.

oslImageIsMirroredV

#define oslImageIsMirroredV

(

img

)

Value:

((img)->offsetY1 > (img)->offsetY0)

Returns whether the image is mirrored vertically.

This macro checks if the image has been mirrored vertically. An image is considered to be mirrored vertically if the y-coordinate of the bottom-right corner (offsetY1) is greater than the y-coordinate of the top-left corner (offsetY0).

Parameters

img	The image to check for vertical mirroring.

Returns

Returns true if the image was mirrored vertically, false otherwise.

See also

Use oslMirrorImageV to mirror the Images vertically.

oslImageRotMoveX

#define oslImageRotMoveX	(		img,
			x )

Value:

((((x) + (img)->centerX * (img)->stretchX) / (img)->sizeX))

Calculates the x-coordinate for moving an image so that its top-left corner is at the specified position when no rotation is applied.

This macro computes the x-coordinate for positioning an image's top-left corner at (x, y) considering the image's rotation parameters. It takes into account the rotation center and the size of the image.

Parameters

img	The image to position.
x	The desired x-coordinate for the top-left corner of the image.

Returns

The x-coordinate adjusted for the rotation center.

See also

Use oslImageRotMoveY for the y-coordinate.

oslImageRotMoveY

#define oslImageRotMoveY	(		img,
			y )

Value:

((((y) + (img)->centerY * (img)->stretchY) / (img)->sizeY))

Calculates the y-coordinate for moving an image so that its top-left corner is at the specified position when no rotation is applied.

This macro computes the y-coordinate for positioning an image's top-left corner at (x, y) considering the image's rotation parameters. It takes into account the rotation center and the size of the image.

Parameters

img	The image to position.
y	The desired y-coordinate for the top-left corner of the image.

Returns

The y-coordinate adjusted for the rotation center.

See also

Use oslImageRotMoveX for the x-coordinate.

oslSetImageRotCenter

#define oslSetImageRotCenter

(

img

)

Value:

((img)->centerX = (int)oslAbs((img)->offsetX1 - (img)->offsetX0) >> 1, (img)->centerY = (int)oslAbs((img)->offsetY1 - (img)->offsetY0) >> 1)

Sets the rotation center of an image to its center.

This macro sets the rotation center (centerX, centerY) to the middle of the image. This is useful for rotation operations where the center of rotation is typically the middle of the image.

Parameters

img	The image to modify.

See also

Use oslImageSetRotCenter as an alias for this macro.

oslImageSetRotCenter

#define oslImageSetRotCenter   oslSetImageRotCenter

Alias for oslSetImageRotCenter.

This macro is an alias for oslSetImageRotCenter, setting the rotation center to the middle of the image.

Parameters

img	The image to modify.

See also

Use oslSetImageRotCenter for detailed documentation.

oslCorrectImageHalfBorder

#define oslCorrectImageHalfBorder

(

img

)

Value:

((img)->offsetX0 = (img)->offsetX0 + 0.5f, (img)->offsetY0 = (img)->offsetY0 + 0.5f, (img)->offsetX1 = (img)->offsetX1 - 0.5f, (img)->offsetY1 = (img)->offsetY1 - 0.5f, img->stretchX--, img->stretchY--)

Crops 0.5 pixel from each corner of the image.

This macro adjusts the image's borders to eliminate visual artifacts caused by bilinear filtering when the image is stretched. By cropping 0.5 pixel from each corner, it helps prevent unwanted borders that might appear around the image.

Parameters

img	The image to correct.

Note

This is a hacky routine and should be used carefully. It's intended for use with bilinear filtering and stretched images.

oslResetImageHalfBorder

#define oslResetImageHalfBorder

(

img

)

Value:

((img)->offsetX0 = (img)->offsetX0 - 0.5f, (img)->offsetY0 = (img)->offsetY0 - 0.5f, (img)->offsetX1 = (img)->offsetX1 + 0.5f, (img)->offsetY1 = (img)->offsetY1 + 0.5f, img->stretchX++, img->stretchY++)

Undoes the effect of oslCorrectImageHalfBorder.

This macro reverts the adjustments made by oslCorrectImageHalfBorder. It should be used with caution, as calling it without a preceding oslCorrectImageHalfBorder or calling it multiple times may lead to incorrect image adjustments.

Parameters

img	The image to reset.

Note

Prefer using oslResetImageTile for more consistent behavior.

oslGetImageWidth

#define oslGetImageWidth

(

img

)

Value:

((int)oslAbs((img)->offsetX1 - (img)->offsetX0))

Returns the width of the image, considering the current frame or tile.

This macro computes the width of the image based on the current frame or tile settings. To retrieve the full image width, use image->sizeX.

Parameters

img	The image to measure.

Returns

The width of the image frame or tile.

oslGetImageHeight

#define oslGetImageHeight

(

img

)

Value:

((int)oslAbs((img)->offsetY1 - (img)->offsetY0))

Returns the height of the image, considering the current frame or tile.

This macro computes the height of the image based on the current frame or tile settings. To retrieve the full image height, use image->sizeY.

Parameters

img	The image to measure.

Returns

The height of the image frame or tile.

oslGetImageSizeX

#define oslGetImageSizeX   oslGetImageWidth

Returns the width of the image, considering the current frame or tile.

This macro is an alias for oslGetImageWidth, providing the width of the image based on the current frame or tile settings. To get the full image width, use image->sizeX.

Parameters

img	The image to measure.

Returns

The width of the image frame or tile.

oslGetImageSizeY

#define oslGetImageSizeY   oslGetImageHeight

Returns the height of the image, considering the current frame or tile.

This macro is an alias for oslGetImageHeight, providing the height of the image based on the current frame or tile settings. To get the full image height, use image->sizeY.

Parameters

img	The image to measure.

Returns

The height of the image frame or tile.