問題描述
這個(gè)問題是問題如何保存的后續(xù)問題Shiny 中的傳單地圖，以及在 Shiny 中保存?zhèn)鲉蔚貓D.
This question is a follow-up to the questions How to save a leaflet map in Shiny, and Save leaflet map in Shiny.
我添加了一個(gè)工具欄來在地圖上繪制形狀/點(diǎn)，它是leaflet.extras 包中的addDrawToolbar.這讓用戶可以交互式地繪制線條、形狀…….最后，我希望能夠?qū)в欣L制形狀的地圖保存為 pdf 或 png.
I add a toolbar to draw shapes/points on the map that is addDrawToolbar in the leaflet.extras package. That lets users to draw lines, shapes, ... interactively. In the end I want one to be able to save the map with the drawn shapes as a pdf or png.
我利用問題的答案編寫了以下代碼:如何在 Shiny 中保存?zhèn)鲉蔚貓D.但這無助于實(shí)現(xiàn)我的目標(biāo).
I have coded up the following making use of the answer to the question: How to save a leaflet map in Shiny. But it does not help achieve my goal.
有沒有人可以幫助我?
library(shiny)
library(leaflet)
library(leaflet.extras)
library(mapview)
ui <- fluidPage(
leafletOutput("map"),
br(),
downloadButton("download_pdf", "Download .pdf")
)
server <- function(input, output, session) {
foundational_map <- reactive({
leaflet() %>%
addTiles()%>%
addMeasure(
primaryLengthUnit = "kilometers",
secondaryAreaUnit = FALSE
)%>%
addDrawToolbar(
targetGroup='draw',
editOptions = editToolbarOptions(selectedPathOptions =
selectedPathOptions()),
polylineOptions = filterNULL(list(shapeOptions =
drawShapeOptions(lineJoin = "round",
weight = 3))),
circleOptions = filterNULL(list(shapeOptions =
drawShapeOptions(),
repeatMode = F,
showRadius = T,
metric = T,
feet = F,
nautic = F))) %>%
setView(lat = 45, lng = 9, zoom = 3) %>%
addStyleEditor(position = "bottomleft",
openOnLeafletDraw = TRUE)
})
output$map <- renderLeaflet({
foundational_map()
})
user_created_map <- reactive({
foundational_map() %>%
setView(lng = input$map_center$lng, lat = input$map_center$lat,
zoom = input$map_zoom)
})
output$download_pdf <- downloadHandler(
filename = paste0("map_", Sys.time(), ".pdf"),
content = function(file) {
mapshot(user_created_map(), file = file)
}
)
}
shinyApp(ui = ui, server = server)
推薦答案
顯然 mapshot 函數(shù)不知道繪制的多邊形，只存儲干凈的傳單地圖，因?yàn)樗鼏?dòng)了一個(gè)隔離的后臺進(jìn)程捕獲網(wǎng)絡(luò)快照.
Apparently the mapshot function is not aware of drawn polygons and just stores the clean leaflet-map, as it launches an isolated background process which captures the webshot.
我會提出這個(gè)解決方法，它捕獲整個(gè)屏幕(使用這個(gè) batch-file) 并將其保存為 png.(僅適用于 Windows)
I would propose this workaround, which captures the whole screen (using this batch-file) and saves it as png. (only for Windows)
這不是很漂亮，因?yàn)樗€會捕獲窗口和瀏覽器菜單欄，盡管可以在批處理文件中進(jìn)行調(diào)整.
This is not very beautiful as it will also capture the windows and browser menu bars, although that could be adapted in the batch-file.
批處理文件必須在同一目錄中，并且必須命名為 screenCapture.bat.
The batch-file must be in the same directory and must be named screenCapture.bat .
library(shiny)
library(leaflet)
library(leaflet.extras)
library(mapview)
ui <- fluidPage(
leafletOutput("map"),
actionButton("download_pdf", "Download .pdf")
)
server <- function(input, output, session) {
foundational_map <- reactive({
leaflet() %>%
addTiles()%>%
addMeasure(
primaryLengthUnit = "kilometers",
secondaryAreaUnit = FALSE
)%>%
addDrawToolbar(
targetGroup='draw',
editOptions = editToolbarOptions(selectedPathOptions =
selectedPathOptions()),
polylineOptions = filterNULL(list(shapeOptions =
drawShapeOptions(lineJoin = "round",
weight = 3))),
circleOptions = filterNULL(list(shapeOptions =
drawShapeOptions(),
repeatMode = F,
showRadius = T,
metric = T,
feet = F,
nautic = F))) %>%
setView(lat = 45, lng = 9, zoom = 3) %>%
addStyleEditor(position = "bottomleft",
openOnLeafletDraw = TRUE)
})
output$map <- renderLeaflet({
foundational_map()
})
user_created_map <- reactive({
foundational_map()
})
## observeEvent which makes a call to the Batch-file and saves the image as .png
observeEvent(input$download_pdf, {
img = paste0("screen", runif(1,0,1000), ".png")
str = paste('call screenCapture ', img)
shell(str)
})
}
shinyApp(ui = ui, server = server)
為了刪除瀏覽器和 Windows 工具欄，我像這樣操作 .bat 文件:
To remove the browser and Windows toolbar, I manipulated the .bat-file like this:
第 66 行:
int height = windowRect.bottom - windowRect.top - 37;
第 75 行:
GDI32.BitBlt(hdcDest, 0, -80, width, height, hdcSrc, 0, 0, GDI32.SRCCOPY);
這適用于我的機(jī)器，但您必須調(diào)整這些值，甚至想出更好的解決方案，因?yàn)槲也坏貌怀姓J(rèn)我不太擅長批處理腳本.這將隱藏工具欄，但底部會有一個(gè)黑色條帶.
This works on my machine, but you will have to adapt the values or even come up with a better solution, since I have to admit that I'm not too good at batch scripting. This will hide the toolbars, but there will be a black strip at the bottom.
這篇關(guān)于如何在 Shiny 中保存帶有繪制形狀/點(diǎn)的傳單地圖?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！