library(grid)
library(RGraphics)

# Four arrangements, with aspect ratios
# 4:1, 3:2, 1:1, 2:3, 1:4

boxSize <- .5

calcLayout <- function() {
    # Determine current device aspect ratio
    width <- convertWidth(unit(1, "npc"), "inches", valueOnly=TRUE)
    height <- convertHeight(unit(1, "npc"), "inches", valueOnly=TRUE)
    aspect <- log(height/width)
    if (aspect > (log(4) + log(1.5))/2)
        layout <- 1 # c(4, 1)
    else if (aspect >  (log(1.5) + log(1))/2)
        layout <- 2 # c(3, 2)
    else if (aspect > (log(1) + log(2/3))/2)
        layout <- 3 # c(2, 2)
    else if (aspect > (log(2/3) + log(.25))/2)
        layout <- 4 # c(2, 3)
    else
        layout <- 5 # c(1, 4)
    layout
}

layoutRows <- function(layout) {
    switch(layout, 4, 3, 2, 2, 1)
}

layoutCols <- function(layout) {
    switch(layout, 1, 2, 2, 3, 4)
}

layoutRow <- function(layout, i) {
    switch(layout,
           switch(i, 1, 2, 3, 4),
           switch(i, 1, 2, 3, 3),
           switch(i, 1, 2, 2, 1),
           switch(i, 1, 2, 2, 2),
           switch(i, 1, 1, 1, 1))
}

layoutCol <- function(layout, i) {
    switch(layout,
           switch(i, 1, 1, 1, 1),
           switch(i, 1, 1, 1, 2),
           switch(i, 1, 1, 2, 2),
           switch(i, 1, 1, 2, 3),
           switch(i, 1, 2, 3, 4))
}

lineX <- function(layout, i, rr) {
    switch(layout,
           switch(i, c(.5, .5), c(.5, .5), c(.5, .5)),
           switch(i, c(.5, .5), c(.5, .5),
                  c(.5 + boxSize/2, 1.5 - boxSize/2)),
           switch(i, c(.5, .5), 
                  c(.5 + boxSize/2, 1.5 - boxSize/2),
                  c(.5, .5)),
           switch(i, c(.5, .5), 
                  c(.5 + boxSize/2, 1.5 - boxSize/2),
                  c(.5 + boxSize/2, 1.5 - boxSize/2)),
           switch(i, c(.5 + boxSize/2, 1.5 - boxSize/2),
                  c(.5 + boxSize/2, 1.5 - boxSize/2),
                  c(.5 + boxSize/2, 1.5 - boxSize/2)))
}

lineY <- function(layout, i, rr) {
    switch(layout,
           switch(i, c(.5 - boxSize/2, -.5 + boxSize/2),
                  c(.5 - boxSize/2, -.5 + boxSize/2),
                  c(.5 - boxSize/2, -.5 + boxSize/2)),
           switch(i, c(.5 - boxSize/2, -.5 + boxSize/2),
                  c(.5 - boxSize/2, -.5 + boxSize/2),
                  c(.5, .5)),
           switch(i, c(.5 - boxSize/2, -.5 + boxSize/2),
                  c(.5, .5),
                  c(.5 + boxSize/2, 1.5 - boxSize/2)),
           switch(i, c(.5 - boxSize/2, -.5 + boxSize/2),
                  c(.5, .5),
                  c(.5, .5)),
           switch(i, c(.5, .5),
                  c(.5, .5),
                  c(.5, .5)))
}

dynamicGrob <- function() {
    grob(cl="dynamic")
}

grid.dynamic <- function() {
    grid.draw(dynamicGrob())
}

drawDetails.dynamic <- function(x, recording) {
    layout <- calcLayout()
    pushViewport(viewport(layout=grid.layout(layoutRows(layout),
                            layoutCols(layout),
                            respect=TRUE)))
    for (i in 1:4) {
        pushViewport(viewport(layout.pos.col=layoutCol(layout, i),
                              layout.pos.row=layoutRow(layout, i)))
        rr <- roundRect(width=boxSize, height=boxSize,
                        name=paste("rr", i, sep=""),
                        gp=gpar(fill="black"))
        grid.draw(rr)
        grid.text(i, gp=gpar(col="white",
                       fontsize=convertHeight(unit(0.3, "npc"),
                         "points", valueOnly=TRUE)))
        if (i < 4)
            grid.lines(lineX(layout, i, rr), lineY(layout, i, rr),
                       arrow=arrow(length=unit(0.1, "npc")),
                       gp=gpar(lwd=convertHeight(unit(0.01, "npc"),
                                 "points", valueOnly=TRUE)*5*72/96))
        popViewport()
    }
    popViewport()
}

# grid.newpage()
# grid.dynamic()
# Resize window by hand


# Simulated window change
# rows <- 1:9
# cols <- 9:1
# grid.newpage()
# pushViewport(viewport(layout=grid.layout(3, 3, respect=TRUE)))
# for (i in 1:9) {
#     pushViewport(viewport(layout.pos.row=(i - 1) %% 3 + 1,
#                           layout.pos.col=(i - 1) %/% 3 + 1,
#                           layout=grid.layout(1, 1,
#                             widths=cols[i], heights=rows[i], respect=TRUE)))
#     pushViewport(viewport(layout.pos.col=1))
#     grid.rect()
#     grid.draw(demoGrob())
#     popViewport(2)
# }
# upViewport()