Claudio Ortolina
125 lines
3.4 KiB
Elixir
125 lines
3.4 KiB
Elixir
defmodule MusicLibraryWeb.ChartComponents do
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use Phoenix.Component
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@doc """
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Renders a horizontal bar chart.
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## Examples
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<.vertical_bar_chart
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data={[{"Artist 1", 5}, {"Artist 2", 3}]}
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width={400}
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height={300}
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bar_color="rgb(79, 70, 229)"
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/>
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"""
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attr :data, :list, required: true, doc: "List of {label, value} tuples"
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attr :width, :integer, default: 400
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attr :height, :integer, default: 300
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attr :bar_color, :string, default: "rgb(79, 70, 229)"
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attr :class, :string, default: ""
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attr :label_click, :any, default: nil, doc: "the function for handling phx-click on each label"
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def vertical_bar_chart(assigns) do
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assigns =
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assigns
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|> assign(:padding, 40)
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|> assign(:max_value, max_value(assigns.data))
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# Account for labels
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|> assign(:chart_width, assigns.width - 150)
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# Account for bottom padding
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|> assign(:chart_height, assigns.height - 40)
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|> assign(:bar_height, calculate_bar_height(assigns.data, assigns.height - 40))
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~H"""
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<svg class={@class} width={@width} height={@height}>
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<%!-- X-axis labels and lines --%>
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<%= for {value, x} <- x_axis_values(@max_value, @chart_width) do %>
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<text
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x={x + 150}
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y={@height - 10}
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text-anchor="middle"
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class="text-xs fill-zinc-500 dark:fill-zinc-400"
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>
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{value}
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</text>
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<line
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x1={x + 150}
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y1={@padding / 2}
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x2={x + 150}
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y2={@height - @padding / 2}
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stroke="rgb(228, 228, 231)"
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stroke-width="1"
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stroke-dasharray="4,4"
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/>
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<% end %>
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<%!-- Bars and labels --%>
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<%= for {{label, value}, index} <- Enum.with_index(@data) do %>
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<% bar_width = @chart_width * value / @max_value %>
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<% y = @padding / 2 + index * (@bar_height + 4) %>
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<%!-- Label --%>
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<text
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x="140"
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y={y + @bar_height / 2 + 4}
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text-anchor="end"
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class={["text-xs fill-zinc-500 dark:fill-zinc-400", @label_click && "cursor-pointer"]}
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phx-click={@label_click && @label_click.(label)}
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>
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{truncate_label(label, 20)}
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</text>
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<%!-- Bar --%>
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<rect
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x="150"
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y={y}
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width={bar_width}
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height={@bar_height}
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fill={@bar_color}
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class="opacity-80 hover:opacity-100 transition-opacity"
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>
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<title>{label}: {value}</title>
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</rect>
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<%!-- Value label --%>
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<text
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x={150 + bar_width + 5}
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y={y + @bar_height / 2 + 4}
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class="text-xs fill-zinc-500 dark:fill-zinc-400"
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>
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{value}
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</text>
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<% end %>
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</svg>
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"""
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end
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defp max_value(data) do
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{_, max} = Enum.max_by(data, fn {_, value} -> value end)
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max
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end
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defp calculate_bar_height(data, available_height) do
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bar_count = length(data)
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max_height = min(30, (available_height - (bar_count - 1) * 4) / bar_count)
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max(20, max_height) |> trunc()
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end
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defp x_axis_values(max_value, width) do
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step = max_value / 5
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0..5
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|> Enum.map(fn i ->
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value = i * step
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x = i * width / 5
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{trunc(value), trunc(x)}
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end)
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end
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defp truncate_label(label, max_length) when byte_size(label) > max_length do
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String.slice(label, 0, max_length - 2) <> ".."
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end
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defp truncate_label(label, _), do: label
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end
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