Rescaling made the plots blurry - shiny fluidrow - r

Question

My goal is to divide the page in four quadrant, each with a separate set of plots.
I have one quadrant ready. It looks ok when it occupies the entire window. I would like to have 4 such panes on a single page. As you can see from the screenshot (of the two upper quadrants), inserting the pane that is already ready in the upper left quadrant results in something very blurry. How can I have the graphs not become blurry?
I used fluidrow, perhaps is this not a good idea?
ui = fluidPage(
fluidRow(
column(6,
fluidRow(
column(8, plotOutput("barChart1", height = 250))
, column(4, plotOutput("compteur1", height = 250))
)
,fluidRow(
column(3,
dateRangeInput(
"dateRange2",
label = "Choose the window:",
start = "2016-09-01"
)
)
, column(3,
selectInput("security", "Index:", selected = worldindices[1]
, list(`World Indices` = worldindices,
`Regional Indices` = regionIndices,
`Country Indices` = countryIndices)
)
)
, column(3,
selectInput("metric", "Metric:", selected = plainMetrics[1]
, list(plainMetrics
, `Valuation Multiples` = valMul
, `Fundamentals` = corpFund)
)
)
)
, plotOutput("chartAggr", height = 250)
)
, column(6, style = "background-color:yellow;", div(style = "height:500px;")
)
)
)
Kind regards
EDIT - FOLLOWING ANSWER BELOW:
Trying to give a higher value to the res parameter of renderPlot on the server side does not seem to work. I gave it for instance the value 128, and get the following result:

Answer 1

In your renderPlot() function on the server pass in the res argument... set it to something higher than the default 72 pixels/inch.
renderPlot(expr, width = "auto", height = "auto", res = 72, ..., env
= parent.frame(), quoted = FALSE, execOnResize = FALSE, outputArgs = list())
Note you may need to adjust the size of your plot and add scrollbars to your containers to accommodate the larger high resolution image.
## Something like this on the server
output$barChart1 <- renderPlot(PLOT(), width = 1000, height = 1000, res = 128)
## Something like this on UI
div(style = 'overflow-x: scroll',
plotOutput("barChart1", inline = TRUE))
)

Answer 2

I know this is an old post, but I thought I'd share my solution to the problem.
I was scaling the height of my plot proportionately to the plot's width in order to fix the aspect ratio using the following renderPlot code:
observeEvent({
input$timelinecontinentselector
input$timelinearrangeselector
input$timelinesmoothselector == TRUE
}, {
output$timeline_plot <- renderPlot({
timeline_plotting()
}, height = function() {
round(session$clientData$output_timeline_plot_width * 0.4)
})
})
Crucially, without the round() function initially. I can only assume that the expression produced a height value with decimals which caused the renderer to struggle. The issue disappeared once the value was rounded to a whole number.