Using Print Composer
Before you start to work with the print composer, you need to load some raster and vector layers in the QGIS map canvas and adapt their properties to suite your own convinience. After everything is rendered and symbolized to your liking you click the mActionFilePrintPrint Composer icon. <P>
<P> Opening the print composer provides you with a blank canvas to which you can add the current QGIS map canvas, legend, scalebar, images and text. Figure <A HREF="#fig:print_composer_blank">37</A> shows the initial view of the print composer with an activated Snap to grid modus but before any elements are added. The print composer provides two tabs:
- The General tab allows you to set paper size, orientation, the print quality for the output file in dpi and to activate snapping to a grid of a defined resolution. Please note, the Snap to grid feature only works, if you define a grid resolution > 0. Furthermore you can also activate the Print as raster checkbox. This means all elements will be rastered before printing or saving as Postscript of PDF.
- The Item tab displays the properties for the selected map element. Click the mActionSelectPanSelect/Move item icon to select an element (e.g. legend, scalebar or label) on the canvas. Then click the Item tab and customize the settings for the selected element.
<P> You can add multiple elements to the composer. It is also possible to have more than one map view or legend or scalebar in the print composer canvas. Each element has its own properties and in the case of the map, its own extent.
Adding a current QGIS map canvas to the Print Composer
<P> To add the QGIS map canvas, click on the mActionAddRasterLayerAdd new map from QGIS map canvas button in the print composer toolbar and drag a rectangle on the composer canvas with the left mouse button to add the map. You will see an empty box with a "Map will be printed here" message. To display the current map, you can choose between three different modes in the map Item tab:
- PreviewRectangle is the default setting. It only displays an empty box with a message "Map will be printed here".
- PreviewCache renders the map in the current screen resolution. If case you zoom in or out the composer window, the map is not rendered again but the image will be scaled.
- PreviewRender means, that if you zoom in or out the composer window, the map will be rendered again, but for space reasons, only up to a maximum resolution.
<P> You can resize the map later by clicking on the mActionSelectPanSelect/Move item button, selecting the element, and dragging one of the blue handles in the corner of the map. With the map selected, you can now adapt more properties in the map Item tab. Resize the map item specifying the width and height or the scale. Define the map extend using Y and X min/max values or clicking the set to map canvas extend button. Update the map preview and select, whether to see a preview from cache or an empty rectangle with a "Map will be printed here" message. Define colors and outline width for the element frame, set a background color and opacity for the map canvas. And you can also select or unselect to display an element frame with the frame checkbox (see Figure <A HREF="#fig:print_composer_map_item">38</A>). If you change the view on the QGIS map canvas by zooming or panning or changing vector or raster properties, you can update the print composer view selecting the map element in the print composer and clicking the Update Preview button in the map Item tab (see Figure <A HREF="#fig:print_composer_map_item">38</A>).
<P> To move layers within the map element select the map element, click the mActionMoveItemContentMove item content icon and move the layers within the map element frame with the left mouse button.
- <A NAME="tex2html46" HREF="node4.html">Navigation tools</A>
- <A NAME="tex2html47" HREF="node5.html">Adding other elements to the Print Composer</A>
- <A NAME="tex2html48" HREF="node6.html">Raise, lower and align elements</A>
- <A NAME="tex2html49" HREF="node7.html">Creating Output</A>
- <A NAME="tex2html50" HREF="node8.html">Saving and loading a print composer layout</A>