Loading manual/architecture.md 0 → 100644 +113 −0 Original line number Diff line number Diff line Architecture ============ This page contains a high level explanation of the internal steps performed to render an illustration. The intended target audience are PlotFX developers and users that wish to "look behind the curtain". If you're just trying to get started with using PlotFX, it is not nesseccarily recommended to read this page first as all the nitty gritty details might be confusing at fist. ### Step 1: Configuration ### Step 2: Layouting ### Step 3: Rendering Before the document, consisting of a tree of `Element`s is rendered, a layouting step is performed. Elements -------- ### Element Tree ### Element Interface Layout Rules ------------ Note that the layouting rules described in this section are not exposed to normal users of the PlotFX program. ... normal users are not required to understand these. ### Layout Hint Each elements specifies it's preferred 'placement'. The placement dscribes how the element wishes to be placed with relation to a parent bounding box. It can take any of the following values: - FILL - TOP - RIGHT - BOTTOM - LEFT To understand what these values mean consider the following "virtual" box. The virtual box is divided into five partially overlapping regions: [figure] ### Element placement The process of placing elements on their final positions in the document is called 'layouting'. The layout process is, in principle, a simple depth-first iteration of the element tree. At each step, a "bounding box" (i.e. a clipping rectangle) for every element is calculated from the parent's bounding box. Let's first consider the simple case where the element tree has a depth of one, i.e. it contains the virtual root node and a list of sibling elements which descend from the root node. The initial parent bounding box is by definition set to the size of the document (i.e. width=100% height=100%). Note that this process assumes that an absolute document size is already known. To find the bounding boxes for the elements, we first consider all children that have requested an ... placement. For each element, we compute the elements bounding box as the respective sub-region of the current bounding box and then store it. We then contract the current parent bounding box for the next step to exclude the elements bounding box. This is done in the order in which the elements were defined. Once we have placed all ... elements using this method, we simply copy the remaining bounding box to children that have requested `fill` placement. This process continues recursively for nested elements (i.e. elements that have children). Note that while each element has to respect the layout rules described above when placing its children it is free to use any parent bounding that is a sub-region of it's own bounding box. It is also allowed to use a different parent bounding box for each child element. This is required to implement layout container elements such as `grid` or `legend`. ### Finding the document size ---- --- The layout process starts on the root node. The initial bounding box is the bounding box that spans the full document (i.e. width=100% height=100%). In the first step, all children of the root node are placed in the initial bounding box using a simple scheme called 'group layout'. For elements that contain child elements, this process continues recursively. The group layout scheme is described below in more detail, but the short version is that by default is will simply place all child elements on top of each other. ### Custom Layout Rules Loading
manual/architecture.md 0 → 100644 +113 −0 Original line number Diff line number Diff line Architecture ============ This page contains a high level explanation of the internal steps performed to render an illustration. The intended target audience are PlotFX developers and users that wish to "look behind the curtain". If you're just trying to get started with using PlotFX, it is not nesseccarily recommended to read this page first as all the nitty gritty details might be confusing at fist. ### Step 1: Configuration ### Step 2: Layouting ### Step 3: Rendering Before the document, consisting of a tree of `Element`s is rendered, a layouting step is performed. Elements -------- ### Element Tree ### Element Interface Layout Rules ------------ Note that the layouting rules described in this section are not exposed to normal users of the PlotFX program. ... normal users are not required to understand these. ### Layout Hint Each elements specifies it's preferred 'placement'. The placement dscribes how the element wishes to be placed with relation to a parent bounding box. It can take any of the following values: - FILL - TOP - RIGHT - BOTTOM - LEFT To understand what these values mean consider the following "virtual" box. The virtual box is divided into five partially overlapping regions: [figure] ### Element placement The process of placing elements on their final positions in the document is called 'layouting'. The layout process is, in principle, a simple depth-first iteration of the element tree. At each step, a "bounding box" (i.e. a clipping rectangle) for every element is calculated from the parent's bounding box. Let's first consider the simple case where the element tree has a depth of one, i.e. it contains the virtual root node and a list of sibling elements which descend from the root node. The initial parent bounding box is by definition set to the size of the document (i.e. width=100% height=100%). Note that this process assumes that an absolute document size is already known. To find the bounding boxes for the elements, we first consider all children that have requested an ... placement. For each element, we compute the elements bounding box as the respective sub-region of the current bounding box and then store it. We then contract the current parent bounding box for the next step to exclude the elements bounding box. This is done in the order in which the elements were defined. Once we have placed all ... elements using this method, we simply copy the remaining bounding box to children that have requested `fill` placement. This process continues recursively for nested elements (i.e. elements that have children). Note that while each element has to respect the layout rules described above when placing its children it is free to use any parent bounding that is a sub-region of it's own bounding box. It is also allowed to use a different parent bounding box for each child element. This is required to implement layout container elements such as `grid` or `legend`. ### Finding the document size ---- --- The layout process starts on the root node. The initial bounding box is the bounding box that spans the full document (i.e. width=100% height=100%). In the first step, all children of the root node are placed in the initial bounding box using a simple scheme called 'group layout'. For elements that contain child elements, this process continues recursively. The group layout scheme is described below in more detail, but the short version is that by default is will simply place all child elements on top of each other. ### Custom Layout Rules
