Drawing text

OPENRNDR comes with support for rendering bitmap text. There are two modes of operation for writing text, a direct mode that simply writes a string of text at the requested position, and a more advanced mode that can place texts in a designated text area.

Simple text rendering

To render simple texts we first make sure a font is loaded and assigned to drawer.fontMap, we then use drawer.text to draw the text.

fun main() = application {
    program {
        val font = loadFont("data/fonts/default.otf", 48.0)
        extend {
            drawer.clear(ColorRGBa.PINK)
            drawer.fontMap = font
            drawer.fill = ColorRGBa.BLACK
            drawer.text("HELLO WORLD", width / 2.0 - 100.0, height / 2.0)
        }
    }
}

Link to the full example

Advanced text rendering

OPENRNDR comes with a Writer class that allows for basic typesetting. The Writer tool is based on the concept of text box and a cursor.

Its use is easiest demonstrated through an example:

fun main() = application {
    configure {
        width = 770
        height = 578
    }
    program {
        val font = loadFont("data/fonts/default.otf", 24.0)
        extend {
            drawer.clear(ColorRGBa.PINK)
            drawer.fontMap = font
            drawer.fill = ColorRGBa.BLACK
            
            writer {
                newLine()
                text("Here is a line of text..")
                newLine()
                text("Here is another line of text..")
            }
        }
    }
}

Link to the full example

Specifying the text area

The box field of Writer is used to specify where text should be written. Let’s set the text area to a 300 by 300 pixel rectangle starting at (40, 40).

We see that the text is now drawn with margins above and left of the text, and that the second line of text is set on two rows.

fun main() = application {
    configure {
        width = 770
        height = 578
    }
    program {
        val font = loadFont("data/fonts/default.otf", 24.0)
        extend {
            drawer.clear(ColorRGBa.PINK)
            drawer.fontMap = font
            drawer.fill = ColorRGBa.BLACK
            
            writer {
                box = Rectangle(40.0, 40.0, 300.0, 300.0)
                newLine()
                text("Here is a line of text..")
                newLine()
                text("Here is another line of text..")
            }
        }
    }
}

Link to the full example

Text properties

Text tracking -the horizontal space between characters- and leading -the vertical space between lines- can be set using Writer.style.leading and Writer.style.tracking.

fun main() = application {
    configure {
        width = 770
        height = 578
    }
    program {
        val font = loadFont("data/fonts/default.otf", 24.0)
        extend {
            drawer.clear(ColorRGBa.PINK)
            drawer.fontMap = font
            drawer.fill = ColorRGBa.BLACK
            
            writer {
                // -- animate the text leading
                leading = cos(seconds) * 20.0 + 24.0
                // -- animate the text tracking
                tracking = sin(seconds) * 20.0 + 24.0
                box = Rectangle(40.0, 40.0, width - 80.0, height - 80.0)
                newLine()
                text("Here is a line of text..")
                newLine()
                text("Here is another line of text..")
                newLine()
                text("Let's even throw another line of text in, for good measure! yay")
            }
        }
    }
}

Link to the full example

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