ee_utils_gif_annotate: Add text to a GIF

In csaybar/rgee: R Bindings for Calling the 'Earth Engine' API

Description

Add text to a GIF (magick-image object). This function is a wrapper around image_annotate.

Usage

ee_utils_gif_annotate(
  image,
  text,
  gravity = "northwest",
  location = "+0+0",
  degrees = 0,
  size = 20,
  font = "sans",
  style = "normal",
  weight = 400,
  kerning = 0,
  decoration = NULL,
  color = NULL,
  strokecolor = NULL,
  boxcolor = NULL
)

Arguments

image	magick image object returned by magick::image_read() or magick::image_graph()
text	character vector of length equal to 'image' or length 1
gravity	string with gravity value from gravity_types.
location	geometry string with location relative to gravity
degrees	rotates text around center point
size	font-size in pixels
font	string with font family such as "sans", "mono", "serif", "Times", "Helvetica", "Trebuchet", "Georgia", "Palatino" or "Comic Sans".
style	value of style_types for example "italic"
weight	thickness of the font, 400 is normal and 700 is bold.
kerning	increases or decreases whitespace between letters
decoration	value of decoration_types for example "underline"
color	a valid color string such as "navyblue" or "#000080". Use "none" for transparency.
strokecolor	a color string adds a stroke (border around the text)
boxcolor	a color string for background color that annotation text is rendered on.

Value

A magick-image object

Author(s)

Jeroen Ooms

See Also

Other GIF functions: ee_utils_gif_creator(), ee_utils_gif_save()

Examples

## Not run: 
library(rgee)

ee_Initialize()

col <- ee$ImageCollection("JRC/GSW1_1/YearlyHistory")$map(function(img) {
  year <- img$date()$get("year")
  yearImg <- img$gte(2)$multiply(year)
  despeckle <- yearImg$connectedPixelCount(15, TRUE)$eq(15)
  yearImg$updateMask(despeckle)$selfMask()$set("year", year)
})

appendReverse <- function(col) col$merge(col$sort('year', FALSE))

# -----------------------------------
# 1 Basic Animation - Ucayali Peru
# -----------------------------------

bgColor = "FFFFFF" # Assign white to background pixels.
riverColor = "0D0887" # Assign blue to river pixels.

## 1.1 Create the dataset
annualCol = col$map(function(img) {
  img$unmask(0)$
    visualize(min = 0, max = 1, palette = c(bgColor, riverColor))$
    set("year", img$get("year"))
})
basicAnimation <- appendReverse(annualCol)


## 1.2 Set video arguments
aoi <- ee$Geometry$Rectangle(-74.327, -10.087, -73.931, -9.327)
videoArgs = list(
  dimensions = 600, # Max dimension (pixels), min dimension is proportionally scaled.
  region = aoi,
  framesPerSecond = 10
)

## 1.2 Download, display and save the GIF!
animation <- ee_utils_gif_creator(basicAnimation, videoArgs, mode = "wb")
get_years <- basicAnimation$aggregate_array("year")$getInfo()
animation %>%
  ee_utils_gif_annotate("Ucayali, Peru") %>%
  ee_utils_gif_annotate(get_years, size = 15, location = "+90+40",
                        boxcolor = "#FFFFFF") %>%
  ee_utils_gif_annotate("created using {magick} + {rgee}",
                        size = 15, font = "sans",location = "+70+20") ->
  animation_wtxt
gc(reset = TRUE)
ee_utils_gif_save(animation_wtxt, path = paste0(tempfile(), ".gif"))

## End(Not run)

csaybar/rgee documentation built on March 11, 2021, 5:48 a.m.