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Magick shiny demo
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# Minimal example of Shiny widget using 'magick' images | |
ui <- fluidPage( | |
titlePanel("Magick Shiny Demo"), | |
sidebarLayout( | |
sidebarPanel( | |
fileInput("upload", "Upload new image", accept = c('image/png', 'image/jpeg')), | |
textInput("size", "Size", value = "500x500"), | |
sliderInput("rotation", "Rotation", 0, 360, 0), | |
sliderInput("blur", "Blur", 0, 20, 0), | |
sliderInput("implode", "Implode", -1, 1, 0, step = 0.01), | |
checkboxGroupInput("effects", "Effects", | |
choices = list("negate", "charcoal", "edge", "flip", "flop")) | |
), | |
mainPanel( | |
imageOutput("img") | |
) | |
) | |
) | |
server <- function(input, output, session) { | |
library(magick) | |
# Start with placeholder img | |
image <- image_read("https://images-na.ssl-images-amazon.com/images/I/81fXghaAb3L.jpg") | |
observeEvent(input$upload, { | |
if (length(input$upload$datapath)) | |
image <<- image_read(input$upload$datapath) | |
info <- image_info(image) | |
updateCheckboxGroupInput(session, "effects", selected = "") | |
updateTextInput(session, "size", value = paste(info$width, info$height, sep = "x")) | |
}) | |
# A plot of fixed size | |
output$img <- renderImage({ | |
# Boolean operators | |
if("negate" %in% input$effects) | |
image <- image_negate(image) | |
if("charcoal" %in% input$effects) | |
image <- image_charcoal(image) | |
if("edge" %in% input$effects) | |
image <- image_edge(image) | |
if("flip" %in% input$effects) | |
image <- image_flip(image) | |
if("flop" %in% input$effects) | |
image <- image_flop(image) | |
# Numeric operators | |
tmpfile <- image %>% | |
image_rotate(input$rotation) %>% | |
image_implode(input$implode) %>% | |
image_blur(input$blur, input$blur) %>% | |
image_resize(input$size) %>% | |
image_write(tempfile(fileext='jpg'), format = 'jpg') | |
# Return a list | |
list(src = tmpfile, contentType = "image/jpeg") | |
}) | |
} | |
shinyApp(ui, server) |
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