The main difference between the native classes and the non-native ones is that the native ones do not perform exactly the same in all platforms, because the drawing is done by the underlying platform itself. lazcanvas: TLazCanvas is a non-native Canvas which can draw to an image in a TLazIntfImage.intfgraphics: TLazIntfImage is an image which attaches itself to a TRawImage and takes care of converting between TFPColor and the real pixel format of the TRawImage.graphtype: TRawImage is the storage and description of a memory area which contains an image.In Windows it is very fast because Windows allows creating a locally allocated image which can receive drawings from a Windows Canvas.īesides these there are also non-native drawing classes located in the units: TRasterImage (usually used via its descendant TBitmap) is a memory area reserved for drawing graphics, but it is created for maximum compatibility with the native Canvas and therefore in LCL-Gtk2 in X11 it is located in the X11 server, which makes pixel access via the Pixels property extremely slow. TFont, TBrush and TPen describe how the drawing of various operations will be executed in the Canvas. It cannot exist alone and must either be attached to something visible (or at least which may possibly be visible), such as a visual control descending from TControl, or be attached to an off-screen buffer from a TRasterImage descendent (TBitmap is the most commonly used). TCanvas is a class capable of executing drawings. These classes are: TBitmap, TCanvas, TFont, TBrush, TPen, TPortableNetworkGraphic, etc. The native classes are mostly located in the unit Graphics of the LCL. Native graphics classes are the most traditional way of drawing graphics in the LCL and are also the most important one, while the non-native classes are complementary, but also very important. The Lazarus Component Library (LCL) provides two kinds of drawing class: Native classes and non-native classes. Introduction to the Graphics model of the LCL Graphics libraries - here you can see the main graphic libraries you can use to develop. 12.2 Example 2: Drawing on controls of Form.12.1 Example 1: Drawing on loaded JPEG with TImage.7.3 Create a custom control which draws itself.7.1.3 Painting on the volatile visual area of the TImage.7.1.2 Painting on the bitmap of a TImage.7 Motion Graphics - How to Avoid flickering.6.8 Using the non-native StretchDraw from LazCanvas.6.7 Conversion between TLazIntfImage and TBitmap.6.4 Creating and drawing a transparent bitmap for a TImage.6.3 Loading a TLazIntfImage into a TImage.6 Working with TLazIntfImage, TRawImage and TLazCanvas.5.6 Drawing alpha-channel transparent bitmaps.5.1 Loading/Saving an image from/to the disk.5 Working with TBitmap and other TGraphic descendents.4.4 Drawing text with sharp edges (non antialiased).4.3 Drawing text to an exactly fitting width.2 Introduction to the Graphics model of the LCL.You are to investigate the distribution of 0s in rows of the pattern emanating from a single dot. (image below from deprecated 'Patterns' applet) (Please note that when the number of rows is close to the maximum of 50, the drawing is slow. The apex of the triangle is still clickable. You can also chose to see a pure triangle with a single node in the upper row.So that the colors are in a sense reversed. In this case, the pattern consists of two colors only with 0 using the foreground color. By checking "Multiplies" you request to associate all nonzero digits with a single color. When creating a new pattern, you can select to get a single nonzero digit in the upper row, or a random pattern, or the whole upper row carrying the same digit (1).With every click the digit (or the corresponding color) cycles through the sequence of residues 0, 1, 2, 3. Every dot in the upper row is clickable.All omitted nodes are assigned the value of 0. Think of the applet as presenting a finite view of an infinite lattice of nodes filling the lower half plane. Where N is the modulus of the arithmetic used. Patterns in the drawing area are defined row-by-row starting from the upper row which consists of clickable digits (or circles.) The value p of a node is defined by values (q1 and q2) of the two nodes immediately above it according to the following formula: In the drawing area of the applet below, we have either rows of digits or circles with colors corresponding to the digits. Dot Patterns, Pascal Triangle and Lucas Theorem
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